Immortal Procreation Clause
- The fertility of a species is inversely proportional to its lifespan. Thus, as a species approaches immortality, their birth rate approaches zero.
On its surface, being immortal
is a pretty sweet gig. You have a lot of time on your hands and usually you never have to suffer the effects of injury or old age
Now, the wise group of sages known as Queen
once asked us, "Who Wants to Live Forever?
" and here's one reason why: in many works of fiction featuring immortality, not only do they outlive their mortal lovers
, but the immortals in question also are sterile or infertile: they cannot have children, since children are considered the "normal" way
for mortal humans to ensure their legacy
In many cases, this is an example of Cursed with Awesome
, because, along with some STD Immunity
, it means that the teen-looking ancient
vampire stud can get it on with the ladies as much as he wants without worrying about consequences of any sort, particularly leaving lovers pregnant with a Dhampyr
who will eventually grow up and try to kill him
. Or at least demand child support
Immortals may have methods of making mortals immortal (vampire bite, Applied Phlebotinum
, or the like) and they may come to view those that they bring over into immortality as their own children
, teaching them the lessons and how to thrive as an immortal. This, however, is not the same as having natural children.
Sometimes the beings in question are perfectly able to have children, but are not allowed to, by the laws of their society, because allowing immortals to breed will quickly lead to overpopulation. This usage tends to be found in hard Speculative Fiction
Another common twist is to have immortals that are quite fertile/potent but whose children are completely or near-completely mortal. These examples are also included here because they fit in with the theme that unchecked reproduction combined with immortality is unsustainable. This aversion is probably even more tragic, since the immortal will then be forced to watch their children die as they inevitably outlive them all
In a strictly biological sense this trope is fairly logical. Without death, an immortal population would constantly grow and eventually crowd themselves out and deplete their resources. As such, childbirth isn't really a necessity for such a species, since the members rarely need replacement. The above formula can (loosely) apply to any given species. Not to mention the little fact that females only have a limited amount of eggs in their ovaries, so one can presume
that even if they're blessed with eternal youth, in the end there is no escaping menopause.
This trope includes extremely Long Lived
characters and species with low birth rates, as they fit on the sliding scale properly. The most common example of this is elves; Tolkienesque elves generally are The Ageless
and can have children; their population is mitigated by a low birth rate (a typical elf couple can live together for several thousand years and produce only one or two children in all that time), the occasional violent death, and the tendency for older elves to journey across the sea to a mystical land, never to be seen again
Related to Creative Sterility
; this is a focus on sexual reproduction. Can result in a Dying Race
open/close all folders
Anime and Manga
- In Fullmetal Alchemist, homunculi, creatures created by alchemy, are stated as unable to reproduce. They exist outside of any ecosystem.
- Hohenheim is immortal and can reproduce, but his children aren't abnormal. Except for the, you know, world class alchemist while still in grade school and golden eyes.
- In the 2003 anime, this is Played With : unlike the other homunculi, Pride/Bradley could not reproduce but aged ; his son was entirely human because he is adopted (this plot point gets Lampshaded when they discuss his identity).
- Fullmetal Alchemist Brotherhood :(a reboot of Fullmetal Alchemist) the aforementioned immortal with mentions his children "aren't quite human", but beyond the aforementioned(world-class alchemy and gold eyes), they don't seem all that different.
- Played straight in Mnemosyne until a last minute epilogue subversion: Rin herself bears a child, proving that it is possible.
- In the Metroid manga it's mentioned that the Chozo are slowly becoming extinct because their lengthened lifespan also made them very infertile.
- Mahou Sensei Negima! averts Immortality Begins at Twenty, causing this problem for pre-pubescent immortals. The vampire Evangeline has been around for hundreds of years, and presumably never reproduced. Although this may have more to do with the fact that she's evil, uber powerful, and scary as hell, as well as the fact that she gained immortality when she was ten years old and has been stuck that way since. It probably applies to vampires, in general, as no other ones have ever appeared.
- Makie, Akira, Ako, and Yuuna were briefly vampire-ified by Evangeline in volume 3, but they were apparently cured.
- Negi himself, however, will stop aging "soon". He might still grow up for a few years, or be stuck with the same fate as Evangeline.
- In the Old Shame manga that Hellsing was based on, Proto-Alucard explains that he kills off vampires who Turn too many humans because if there were too many vampires, there wouldn't be
enough any humans left to feed on.
- He bring this up in Chapter 1 as well
- Specifically the reason for the Royals killing each other off in Princess Resurrection. Since a fully mature Royal becomes a Phoenix who literally cannot die, There Can Be Only One to become one.
- The Bounts from Bleach's Bount arc were a group of immortal, soul sucking humans who could summon Bond Creatures, but they were incapable of reproduction. The one Bount that did have the ability to reproduce was killed by her own people as part of some elaborate ritual to summon an army of flying, soul-sucking insects.
- In Dance in the Vampire Bund it's discovered that the "True Blooded" vampires can, in addition to turning those they feed on into theoretically weaker ones, reproduce sexually. Problem is that females can give birth once and they apparently reach adulthood very slowly. Bigger problem is that Dukes Ivanovic, Li, and Rozenmann apparently killed off the other 97 dukes and their families then slaughtered the whole Royal House of Tepes save for the young Princess Mina (who is under obligation to produce a True Blooded heir).
- Huey Laforet in Baccano! procreated after becoming immortal just to see if this applied. His daughter doesn't inherit his immortality.
- The Juraians in Tenchi Muyo! have vast lifespans (one prominent member of the royal family is over 5,000 years old; she looks 35-40, tops), but their birth rates seem to be quite low. The Juraian emperor, for example, has been married to two women (at the same time) for over 700 years, and only had 3 children between them. His mother-in-law (the above-mentioned 5,000 year old Juraian) has only one biological daughter; while she's raised several other children, they were all adopted.
- In JoJo's Bizarre Adventure it is mentioned that the longer a species life span is, the less they reproduce. The pillar men were a long lived species outnumbered by the short lived humans, and when the Big Bad Cars becomes the Ultimate Life Form, it is mentioned that he can no longer reproduce and doesn't need to, as he will never die.
- In Kami-sama no Inai Nichiyoubi, when people lost the ability to die due to God abandoning the world, they also lost the ability to give birth. As pointed out in-series, this makes Ai's existence even more perplexing, as she was born three years after God had abandoned the world.
- Pure-Blooded Devils in High School D×D are implied to have 10,000 year lifespans, and proportionately low fertility. After the Great Offscreen War caused a severe depopulation, with the 72 former great houses being reduced to three and remnants, this has become a serious problem. As of the start of the series, even high-ranking devils of the remaining noble houses are recruiting from humans they personally reincarnate, just to get their numbers back up and stabilize the population.
- Things have gotten so desperate for the devils that it's stated point-blank (in the novels, at least) that Fantastic Racism has been marginalized by how dire the situation is, and even the proudest pure-blooded houses consider blood purity secondary to just surviving. The few who strictly stick to creating pure-blooded peerages are considered shortsighted and selfish by most of the population.
- In Toriko, the Heracs are nearly immortal thanks to their extremely powerful Healing Factor. They also have very low birth rates. The Herac species is in decline because they need "AIR" to reach maturity, and the Nitros have been harvesting "AIR" before the Heracs can reach it for a long time. In the present, the only Herac that can reproduce is the Horse King itself.
- Near the end of Soul Eater, it's revealed that while Lord Death is immortal and was able to have a child, that child unlocking his full power will cause the previous incarnation of death to die.
- In the Wildstorm universe, the effectively immortal Kherubim suffer from an abysmally low birth-rate. Subverted in that it seems they can breed with humans more prolifically than they can with their own kind.
- Most elves of ElfQuest can only breed after a "recognition" (which is basically the instincts or 'lizard brain' of two elves deciding the two are genetically very compatible, and forcing them to conceive a child). One of the stories set before the Original Quest mentions that the tribe's Healer tried, and was in one case successful, to break that limitation, because there were worries the tribe was too small. And later on Leetah managed to induce Recognition for Nightfall and Redlance.
- One tribe of elves had no children for millennia, partly because of stagnation (they were hiding from the world in a "fortress" and would not outgrow it). On the flip side, the Wolfriders have wolf blood, which may make them more fertile; a past chief, Two-Spear, was born to his father's lifemate, not his Recognized mate.
- Being a One-Gender Race, the Amazons of Wonder Woman in Gail Simone's run suffer from this, being reincarnated from women who were killed by men, including many mothers. They make "Whittle Babies" out of wood to keep themselves occupied, and until Diana was created by the Gods at Hippolyta's demand there were no children born on the island. A group of Amazons turned evil primarily because they were jealous that Hippolyta was given a daughter while they remained childless.
- After a retcon, The Eternals are completely infertile with each other, since they are Nigh Invulnerable, simply regenerate when you do hurt them, and are eternally young. Several of them have sired completely normal baseline human offspring with mortal lovers/spouses over the centuries, but this presents other problems. Originally, the Eternals could and did procreate, albeit very rarely and many Eternals were noted as being the children of other Eternals and born long after the Celestials created their race.
- Justified by a similar lack of desire in Undocumented Features. Humans who have taken the Detian treatment can have children. It's just that the current crop of Detians haven't had very many. For instance, Gryphon has been alive for over 400 years, but only started having children in the last couple decades.
- In the Marvel Cinematic Universe fandom, this is a frequently-used fanon for Asgardians.
- In Highlander and its various spin offs, the immortals cannot have children. If you believe the second movie, it's because they're actually from another planet. In the later films (but not in the TV series), Immortals are capable of reproducing until they die for the first time. In the third movie Connor has adopted a kid so he could have a son. This is also a plot point in the fourth and fifth movies.
- The Man from Earth fathered many children during his looooong life, but since he is forced to leave his families after a few years, nothing is known about their immortality, apart from one, and he is most certainly mortal.
- In In Time people can reproduce freely, but to stay alive past the age of 25 you must work to obtain time, which also functions as currency. The practical effect of this is that only the rich are immortal, while the average lifespan is, if anything, far lower than normal thanks to the poor being worked to death by the system to control the population.
- In the Underworld films, the immortal father of the vampire and lycan bloodlines seems to have stopped reproducing after his original three sons. At least, there's no indication that any other Corvinus bloodline existed for Lucien's agents to hunt down.
- Of course, considering that Alexander Corvinus has spent much of his immortal life "cleaning up" after vampires and lycans, keeping the existence of immortals secret, it's also possible he could have had other children in secret. Given how old he is, it could very well be that a good number of people are his descendants and don't know it (it's also made clear that not every descendant carries an inactive form of the immortality virus).
Folklore and Mythology
- While the Greek gods certainly could mate with mortals, the demigod children were, themselves, mortal. A few favored ones like Herakles and Dionysus were later granted full godhood. The gods presumably had kids among themselves less frequently.
- The Titans, on the other hand, frequently had children among themselves.
- Averted in The Bible. Before The Flood, people could live centuries, and were stated to have children, some of them had lots of them.
- The Tucks from Natalie Babbitt's Tuck Everlasting cannot change; they don't age, they don't die. Mrs. Tuck was past childbearing age when she drank from the spring, so it isn't an issue for the elder Tucks. However, the eldest Tuck son got married in the years after they drank from the spring and before they realized its effects; he had children, but his wife eventually thought he'd made a Deal with the Devil and left him.
- Brought up in one of Joanne Bertin's The Last Dragonlord. Dragonlords, the people who shapeshift between dragons and humans, have exceedingly long lifespans; as of the first book, the youngest is really six hundred years old, still looks the same, and is still called "little one." They cannot have children with ordinary humans, and while that does not apply between Dragonlords, they voluntarily do not have children, since when they do reproduce their offspring are very nearly always human. The same Dragonlords who enjoy their human friends and grieve and let go when they age and die have a lot more trouble with it when it's their own children.
- In C. J. Cherryh's Cyteen, it is mentioned in passing that rejuvenation drugs have a side effect of making the user sterile.
- In Guild Hunter:
- Vampires over 200-years-old cannot have children.
- Angels have a very low birth rate, with sometimes decades between two angelic birth on the planet.
- In Mercedes Lackey's Urban Fantasies and Historical Fantasies, the immortal sidhe can reproduce, but it happens extremely infrequently. As a result, children are treasured by both the Unseighlie and Seighlie Sidhe, although only the Seighlie expand this love to human children and try to save them from unpleasant fates.
- Vampires from Meyers's Twilight were believed to be infertile, but it turns out that that only applies to the females. So the guys can still get it on with a human girl, but it's incredibly dangerous for the human woman.
- The same for wolves (though they're really only immortal so long as they shape shift). While there's only been one female wolf, she appears to have become menopausal after she became a wolf. The males can all still have children, a fact which is publicly known because of imprinting.
- A similar situation holds for the werewolves in Patricia Briggs's Mercy Thompson novels. The werewolves don't age (and if they were old when they were turned, they'll revert to looking adult, but permanently young and fit). Male werewolves can have children with ordinary women, but they'll be born mortal, and there's a high risk of miscarriage. Female werewolves can get pregnant, but inevitably miscarry when they change, which they must do at full moon. The only exception is Charles, the son of the Marrok, who is the offspring of two werewolves and was born one; his Native American mother used magic to hold off the change, but the effort depleted her strength and she died in childbirth. It's often a plot point that older werewolves often become unstable because they have outlived too many partners and children - in the Briggs 'verse it's dangerous to try to become a werewolf, as you have to be savaged to the point of death and not many survive the process, so they can't automatically turn their wives and children.
- Vampires in Briggs's 'verse seem not to reproduce in the usual way as they're not so much immortal as undead; they're literally dead during the day. They remain the same age as when they were turned. However, many of them assume a parental responsibility for new vampires that they have turned, and a vampire seethe acts very much like a big dysfunctional mafia family.
- Fae, on the other hand, can have children with mortals or with each other, and how "immortal" the children are seems to vary. There are lots of different kinds of fae and not very many of them in total.
- Used in Terry Pratchett's Strata, in which the universal currency is a life-extension treatment. One of the main characters, who is several centuries old, wonders what life would have been like had she been a "short-lifer" and thus able to have children.
- In Mickey Zucker Reichert's The Renshai Trilogy and its sequel The Renshai Chronicles, it's remarked that the Norse Gods are almost completely infertile, and that many of them had a human parent. In the second trilogy, the life cycle of Elves becomes an important plot point: a new elven child can only be born if one of the currently existing elves dies (freeing their soul for reincarnation), so the Elven population can never grow beyond its current numbers. Furthermore, the elf needs to have died of natural causes - any violent death permanently reduces the maximum elven population.
- There is a cultural mandate against reproduction by immortals in Jitterbug Perfume by Tom Robbins.
- Averted in J. R. R. Tolkien's legendarium, as elves live forever but are perfectly capable of having children. They simply don't choose to do so very often; by the time of The Lord of the Rings, elves are near the end of a very long-term emigration, sailing away from Middle-Earth when they've grown weary of it, so overpopulation isn't a problem. In the stories set in the earliest time periods, though, there are frequently several generations of a single family living and ruling together, making a mental picture far more difficult than the two-generation Hugo Weaving/Liv Tyler pair in the films! There is also the implication that having children can be very spiritually draining for elves, restricting them from having too many. One elf was so diminished by giving birth that she essentially lost the will to live. The endless lives of elves also means that after a relatively short time, sex becomes boring to them. In his notes at one point, Tolkien indicated that elves do not have children after a certain age. (So, menopause?) Also, Fëanor and Nerdanel had the most children that any elven couple ever had, whereas seven children would be, if anything, low for most fertile human couples if they both lived through the women's child-bearing years in most eras.
- The Cracked article 6 Horrifying Implications of Awesome Fantasy Movie Universes discusses this: "no one in the Elfish kingdom is getting any, anywhere."
- Also averted with hobbits, who often have large families despite living longer than humans.
- But played straight with Ents, who live nearly forever but are all male and thus can't reproduce. Presumably wherever the Entwives are they have the opposite problem.
- Roger Zelazny's The Chronicles of Amber series: as the books themselves comment on, the immortal lords of multiverse have been around for millennia, but are not particularly fertile: the first book is Nine Princes In Amber, not Nine Hundred Thousand Princes In Amber. There is reference to several older princes who died "For the good of Amber" though.
- The immortals from The Company Novels, though Mendoza manages to have children later on in the series. Very, very weirdly.
- In Poul Anderson's The Boat of Million Years, the immortals are perfectly capable of reproducing. Unfortunately, the children are never immortal, even when both parents are.
- Completely ignored in Robert A. Heinlein's Time Enough for Love. Many near-immortals live throughout the galaxy and reproduce like bunny rabbits, even if they're 20 centuries old. Their children may also be effectively immortal, depending on what genes they picked up and whether they have access to a rejuvenation clinic. They solve the overpopulation problem by continually colonizing new planets. Justified as reproduction was the entire point of the Howard Families. They were an experiment in human longevity that worked spectacularly well.
- It is worth noting that Tellus Secundus, the planet where the story begins, has an unusually high population of near-immortal "Howards" and in consequence has instigated population controls. The planet's chief executive mentions to Lazarus Long that he'll grant an exception to any woman Lazarus feels like having a child with. Lazarus himself is a special case as, being over two thousand years old and born at the start of the Howard experiment, he can claim over 80 percent of the galactic population and over 99 percent of Howards as his descendants to some degree or another.
- Sort of the case in the universe of the novels American Gods and Anansi Boys with two notable exceptions. In the former, Wednesday (Odin) tells Shadow that people like him generally "shoot blanks" Shadow is Wednesday's son with a human woman, but rather than being a completely new god or simply human, he is an incarnation of the God Baldr. The book also informs the reader in American Gods that Mr. Nancy (Anansi) has a son, Charlie, who is the protagonist of Anansi Boys and is seemingly completely normal. His brother, Spider, who was split from him, is basically a god, although the protagonist turns out to have Reality Warper powers. Charlie ends up having children, who seem to be human while Spider appears to be infertile. Possibly on purpose, considering that the mother-in-law lives within spitting distance of them.
- Played straight so hard it hurts in Fragment. When the protagonists discover the mandatory sentient species that seems to be a part of any Lost World or Alien planet, they discover that they are immortal because they don't have any babies in a combination of Cliché Storm and Artistic License - Biology.
- In Three of Heart, One of Blood, the Legacies are incapable of breeding, though the systems still work. This is a fact that Doryn uses and exploits. A lot.
- In the sci-fi The Declaration by Gemma Malloy, immortality has been made possible. Unfortunately, nobody who "opts-in" is allowed to have children because of this. Any children, or "surpluses," born to people who opt in are sent to group homes and taught that they are worthless beings that do not deserve to exist.
- Fairies in Artemis Fowl (who are not immortal but very long-lived) can only have one child every twenty years; humanity's faster reproduction is actually the main reason it was able to more-or-less take the world from them.
- Witches in Phillip Pullman's His Dark Materials trilogy live roughly a thousand years. They take human men for lovers and bear children; if the children are girls, they're witches and if boys, human and short-lived. Presumably, they don't have children especially often. One character suggests that a witch dies when her heart is so broken from watching her lovers and sons grow old and die that she can't go on.
- Straightforwardly stated in C.S. Friedman's The Madness Season. The vampires of that book are only fertile when they subsist on a diet of willingly provided human blood. This is explained in-text as an evolutionary mechanism to keep them from reproducing in an environment that isn't willing to support new vampires.
- The Marra, as well, are subject to this. Energy beings who are not able to die but can also not create new Marra (or, if they can, they have forgotten how)
- The Culture generally discourages having more than a few children but no one stops those who wants dozens. Given that they have unlimited resources it's not really a problem.
- Averted in Wen Spencer's "Tinker" series. The Oni are immortal and breed like mice. Famines are common in the Oni's overpopulated world. The Elves on the other hand are just as fertile as humans but don't feel the need to have as many children since they are immortal. The population of Elfland has dropped by 50% over the last two thousand years due to war, accidental death, and suicide.
- Unicorns in The Last Unicorn (immortal but can be killed) live solitary lives in separate forests and mate very rarely.
- In Aleksandr Zarevin's Lonely Gods of the Universe, the Human Aliens from the planet Oll arrive to Earth in distant past, escaping from a power-hungry official. They plant some seeds they bring with them to grow food, and the seeds of a salad plant known as ambrosia grow practically overnight. After eating a salad made from ambrosia, they suddenly fall ill and wake up young and immortal. Somehow, an alien plant has acquired entirely new properties on Earth. They make a few locals immortal as well and establish themselves as gods on the island. While the females who become immortal are incapable of conceiving a child, this is absolutely not the case for any immortal male who sleeps with a human woman. That is, in fact, the cause of the many hair colors modern humans have. The original humans all had dark hair, while the Olympians (yes, those Olympians; they also call their island Atlantis after Atl, their home country on Oll) are all redheads. Immortality can only be achieved through consuming a sufficient quantity of ambrosia, which withered and died soon after blooming.
- The Ollans have managed to dry and preserve some ambrosia leaves. One of them is awakened by a Russian man after centuries in stasis. In return, she gives him a full dose. However, he decides to only take half of it and keep the other half for later. The half only heals his grave wounds and extends his life but doesn't turn him young or stop his aging. Later, he gives the other half to the protagonist's friend, who has lost a leg during the Soviet invasion of Afghanistan. The leg grows back overnight.
- In The Mote In Gods Eye series, the Moties invert this - if they don't have children, they die young and horribly. Oh, and the most likable group, the ones who learn English and talk to the humans of the series? They're sterile hybrids. They die after 25 years or so.
- In L. Jagi Lamplighter's Prospero's Daughter trilogy, since the immortality comes from an external source, they are fertile and most have had dozens of children. But the source is not extended to the children or spouses, and so some swore off it.
- Katherine Kerr's Deverry series:
- The Elves of usually live around 500 years, looking young until the last year or two of this, but have very few children during this time. Dallandra discusses the low elven birth rate with Cal and some other elves. It's hypothesized it's not just the length of their lives that restrict their birth rate, it's that part of their diet is meat, and meat-eating animals generally have a comparatively low birth rate. She also compares having children with humans as trading in some of their race's lifespan to have more children.
- Dwarves are also very long lived. Otho lives at least 400 years. Combined with their legendary stubbornness, it makes it very hard for them to let go of grudges.
- In the Witcher cycle, the Elves breed much more slowly than humans, because their women ovulate once in a couple of years (or even tens of years). Not to mention that after a hundred or so years, the sex gets boring. It's also mentioned they're only fertile at young age, but as later in the books a girl is bred with an elf over 500, it's probably only the women.
- In Mikhail Akhmanov's Arrivals from the Dark books, Paul Richard Corcoran, being a Half-Human Hybrid, and his descendants have unnaturaly long lifespans (150-200 years). However, this also means they are highly unlikely to have children until they are well in their 40s or even 50s. This could indicate a slower rate of maturity.
- However, once able to have children, they usually have at least 2. One is noted to have 3 children of her own and then adopting 3 more (keeping a promise she makes at one point).
- Completely averted in Akhmanov's Captain French, or the Quest for Paradise, where humanity has discovered a cure for aging (called Cellular Regeneration, or CR). This doesn't stop people from having kids in the least, and many colonies have to impose Population Control. In fact, the titular character, being quite possibly the oldest human alive (being born in pre-CR days on Earth), has hundreds of thousands of children, although he explains that he didn't technically father any of them save one (his first daughter with his first wife), as they're all the result of artificial insemination with his sperm donated on many planets. However, this trope is, technically, preserved in that the CR treatment is not passed down to children and must be reapplied to everyone once they reach the age they want to be "frozen" in (most choose early 20s, although some prefer ealy 30s).
- Averted in The Dresden Files as well. Wizards are very long-lived (they can be killed, but left to their own devices and otherwise unmolested, they'll go on for centuries), and they can reproduce. Molly Carpenter and Maggie Dresden are wizard children.
- The truly immortal Sidhe are apparently only able to have children with mortals. The child will be born a changeling, and can choose whether to become fully human or fully Sidhe later in life. Since humans have free will and Sidhe don't, it can be a tough choice.
- Georgina Kincaid, succubus, is unable to bear children since she became a succubus.
- In the Tide Lords Tetrology, the immortals cannot interbreed with each other (The union of an immortal egg and an immortal sperm would become immortal at age -9 months and thus never come to term), but they can and frequently have interbred with mortals (There are four entire species who are descended entirely from the mortal offspring of immortals). Said children are always born mortal, but those children whose heritage makes them more than 50% immortal by genetics (Such as an immortal father and one or more immortal ancestors in the mother's line) can potentially become immortal.
- Goes beyond this with the "glorifieds" in the Left Behind book Kingdom Come, since they won't even have the desire for sexual intercourse.
- That's canon. There is no marriage between humans in Heaven. With no marriage and no sin nature, there is neither sex nor the desire for sex, because there is no licit means for sex to occur, nor a desire for anything illicit.
- In Isaac Asimov's story The Last Question, one person states that their supercomputer has solved a lot of problems, but all the solutions were virtually undone when it solved the problem of aging and death.
- The Kantri of Tales of Kolmar can live around two thousand years and are considered mature at two hundred fifty. About two hundred of them fled to the Dragon's Isle five thousand years ago and never increased their numbers. One observes with frustration that they should have increased, but the species seems demoralized and getting more so. There are fewer mated pairs and even fewer births happening all the time. It's mentioned with great concern that there have been only three births in the past eight hundred years - and the Kantri with their huge claws are helpless in the face of complications of birth. If a human hadn't stepped in and midwifed during Song In The Silence, the first birth in three hundred years would have ended tragically. Also, Kantri only feel the desire to have sex a dozen or so times in their long lives, and the act is difficult and painful, not fun. Mated pairs enjoy 'joining souls', but this gets no one pregnant.
- Vampires and werewolves in The Parasol Protectorate cannot sire/bear children after their transformation. Understandable, since Step One in either transformation is "die". With one exception; a supernatural (vampire or werewolf) and a preternatural such as Alexia can produce a child. But this is so rare that no one can confirm this until well into Alexia's pregnancy.
- The Others in Sergey Lukyanenko's Night Watch books are fully capable of reproduction, but their children have just as much chance of being an Other as a child of two Muggles (i.e. very slim). This is why many Others avoid having children, so that they don't have to watch them grow old and die. The Others aren't, technically, immortal, but even the weakest of them can enjoy several centuries of life. The most powerful ones tend to be thousands of years old and not look it. The vampires and werewolves are the exception, as they're able to "initiate" (i.e. bite) their children to turn them. However, vampires and werewolves are the lowers rungs of the Dark Others and are viewed at with little more than disdain. The Light ones see them as nothing more than beasts, while the higher Dark ones consider them cannon fodder. Additionally, they can only feed on humans with a license granted by the Night Watch. Doing so without one is punishable by death.
- Additionally, vampires can only have one child after being turned, at which point their reproductive ability disappears. Nothing of the sort is mentioned for werewolves, but then the author can't seem to decide if they're undead or not.
- According to prot[sic] in the K-PAX novels, since the K-PAXian lifespan is over a thousand years, combined with their unappealing mating process(which involves profound pain, nausea and a bad smell), there's no problem with either under OR overpopulation.
- Amy Thomson said in an interview that "I believe that societies whose individuals have immensely long lifespans, must either have very few young, resulting in a stagnant, inflexible, rigid culture, or else they must place cultural limits on lifespan in order to have the cultural renewal of a younger generation." She chose the latter, so while both the Tendu and the harsels in her books can theoretically live forever if not killed... they don't. Harsels choose to reproduce and die in the act of giving birth to hundreds of nonsentient harlings, which chew their way out of their mother's flesh. Tendu spawn in huge numbers throughout their lives, but they eat their nonsentient young, or otherwise are not concerned by animals eating them. Most adult Tendu select one nonsentient subadult and cause it to metamorphose into an adult which is then cared for and taught, and choose to die soon after this child/apprentice is fully mature; there are a few individuals who choose not to die, and then they are culturally compelled to leave home forever and metamorphose again, becoming sort of wandering judges/problem solvers. This is portrayed as more frightening than death. It's mentioned that there was a time when they did things differently and the ecology was absolutely swamped with Tendu, and there weren't enough resources for everyone.
- Both averted and justified in the Discworld novel Carpe Jugulum. Vampires are perfectly capable of reproducing, through both the bite and the normal way, but they seldom want to because it means more competition for food. Even worse, the vampire parents usually expect their offspring to remain their loving, obedient children for all eternity. This does not go over well with the kids.
- In Lynn Flewelling's Nightrunner series, the human wizards live up to 400 years but are also sterile (and most of them are celibate as well, apparently mostly for cultural reasons). This is actually a problem in the setting, as only humans with some degree of aurenfaie blood can have magic powers and the Aurenfaie have been very isolationist for the last few centuries. So the number of wizards is slowly dwindling, and this is becoming a military disadvatage for the main culture in the story. The royal family, who have an Aurenfaie ancestor a few generations back, live about twice as long as pure humans and most of them can reproduce, though. On the other hand, they don't appear to have any magic talents. The Aurenfaie themselves live 300-400 years and are fertile (the family the reader learns most about had at least 4 children before the mother died) but despite occupying a limited territory, they don't appear to have any population problem. This may be because they don't allow a youngster to marry until he or she is well on their way to their 100th birthday, even though they develop a sex drive somewhere around the age of 20.
- In the short story ''2 B R 0 2 B'' by Kurt Vonnegut, medicine has conquered old age and death. The population numbers are kept under tight control to avoid resource overuse. This means you have to convince someone to volunteer to die in order to have children. The main character's wife is giving birth to triplets...
- In M.C.A. Hogarth's Paradox series the Eldritch live for over a thousand years, but due to complications with their genetic engineering and inbreeding their fertility rate is dropping. Jahir's mother was noteworthy for bearing two children.
- Humanity's Trans Human descendants in the Great Ship series rarely ever have more than one or two children (in normal circumstances) despite living for an hundreds of thousands of years. Part of the low birth rate seems to be implied by parents having to pay for addition berths on the Great Ship. However, their fertility is unchanged - Dream's mother in Eater-Of-Bone had several children; though all but Dream died from malnutrition due to the Lost Colony's near-total absence of metals and salts vital to their augmented metabolism.
- In the fourth book of the Spirit Animals series, the heroes stumble across a town which has been drinking from a magic pool. The pool makes you immortal as long as you keep drinking (if you stop drinking, you die within a few years), but also renders you infertile.
- In Neogicia, a character suspects this is the reason for which the imperial family doesn't share the Bio-Augmentation technology that make its members Long Lived. Also, thanks to that technology being someting that started small and got better over time, the emperor is expected to produce a heir at some point just in case. He's currently more than a thousand year old, looks 35 (his father died around the same age looking like old man) and is still single despite the long line of candidates to be his wife.
- In The Life & Adventures of Santa Claus, none of the immortals are allowed to reproduce, or even seem to have a concept of children—but the idea is so attractive that it prompts Nicele, a nymph, to raise the foundling Santa Claus as her child.
Live Action Television
- Stargate SG-1
- The Asgard are not capable of sexual reproduction; they lost the ability due to extensive genetic alteration. To achieve immortality, they upload clone bodies with their memories when their old bodies die. Eventually even this tactic fails.
- The normal life cycle of Goa'uld includes the spawning of new parasites by extremely rare slug-like queens, with Jaffa specially prepared to incubate the larvae; this almost always happens off-screen.
- Procreation between two Goa'uld hosts is forbidden. The resulting child is very dangerous; thus the practice is proscribed. Such a child, known as a Harcesis, would be born with all the genetic memories of the Goa'uld. Exactly why this would be a bad thing for the Goa'uld is never spelled out but it's probably to prevent Goa'uld secrets from falling into the hands of enemies like the Tokra or the Asgard.
- In the episode "2010" the Aschen weaponized this trope. After making contact with Earth they offered a treatment that would cure all diseases and drastically (though not infinitely) extend human lifetimes. After everybody on the planet got the treatment, SG-1 found out that it had a component not in the original formula; it caused sterility and would lead to the extinction of 90% of humanity. This was that civilization's way of taking over planets without a fight, just a bit of patience. Fortunately, the main characters were able to cook up some time travel gimmick to warn their past selves to not allow this to happen.
- Buffy the Vampire Slayer: With one important exception, the immortal vampires in the Buffyverse cannot create natural children. Even in that one exception, the vampire mother could not bring the child to term the normal way, and the child was mortal anyway.
- Mortal in the age-and-eventually-die way, but he had all the strength, speed, and super senses of a powerful vampire with none of the weaknesses.
- In New Amsterdam, John Amsterdam has had several children, who, unlike him, are mortal. One of these children, Omar, looks older than John himself, and knows about John's immortality.
- One episode shows that John keeps records of his descendants, so he can keep track of them and avoid dating female descendants.
- Both Omar and an elderly female descendant shown in a flashback where John is secretly dating Omar's mother are upset when John tells them that he still hasn't found his soulmate. Of course, what John means is the one woman who would cause his "curse" of immortality to end.
- Captain Jack Harkness, from Torchwood, is another aversion. He's immortal, but can have children. The children, again, are not immortal, thereby preserving the intent of the Clause.
- Given that he's Jack Harkness, he should have lots and lots of children and grandchildren running around if that was the case, not just one family. It makes more sense that the Time Agency routinely sterilised its agents (Would you let people like Jack or John run around in eras without reliable birth control and potentially father their own ancestors?) and that the daughter in season 3 was the result of a 1960s orgy. It's not like Jack is the jealous type who'd refuse to raise the kid as his.
- The fourth series, Miracle Day, is set to involve a thorough subversion of this trope; humanity mysteriously becomes immortal and one of the immediate problems is an impending overpopulation crisis.
- Seems a bit fast though: if the average human lifespan on all of earth is say 50 years, than the population would grow with a staggering 2% a year. This trope only a problem in the long term. (Though in it's defense the show mostly shows us overpopulation in hospitals, which would happen far earlier than overpopulation of earth)
- They also quickly state that humans still age normally. Nursing homes would end up being overpopulated fairly quickliy too.
- The Cylons from Battlestar Galactica are immortal due to their resurrection technology. They are also near-universally infertile, with only a single half-human child born to the entire race.
- One notable exception exists, but did not survive to term
- Inverted with the all-Cylon Thirteenth Tribe. The ancestors of the Final Five could reproduce, so they abandoned their resurrection technology.
- An episode of The Twilight Zone features a movie actress who remained remarkably youthful despite starring in films from the Silent Age (this taking place in the 1960's). She was accompanied by an old woman who acted as a maid. Turns out the actress is none other than Cleopatra, who regains her youth by draining the life force from other people. And the old woman? It's her mortal daughter.
- Doctor Who 's Time Lords live for millenia. Though the TV show never mentions it, this trope is fully in play in the Doctor Who Expanded Universe: the whole species has been infertile for hundreds of thousands of years, and reproduces artificially through "Looms".
- The only reason they are infertile is because the original leader (who was overthrown as a result of a revolution), placed a curse on them that took thousands of years to remove. Odds are that they reproduce like normal humans do, but now have gotten so use to the looms that they stop sexually reproducing.
- In Babylon 5, Lorien mentions that his naturally-immortal species had a very low birthrate, "less than a handful each year". Since their immortality only made them ageless, not indestructible, their population was kept in check by injury or illness.
- A second season episode of Spellbinder has the protagonists end up in a parallel world where, in Victorian times, a deadly plague wiped out a large number of people and threatened to make humans extinct. A cure was found that, miraculously, also made them immortal. Unfortunately, they found out too late that this trope was in full effect. No one subjected to the cure (all survivors) can conceive. Thus, when the protagonists arrive, it's been over 100 years since the plague, and the world still looks like it's in the middle of Victorian times with almost no progress having been made, except with animatronics, which are used to make child-like automatons that the immortals can pretend to be children. When a Mad Scientist finds out that the arrivals (a teenage girl and a 20-some man) are fertile, he kidnaps them, intent on making a fortune by forcing them to make children for the immortals.
- In The Vampire Diaries, vampires cannot procreate. This actually comes up when Elena wonders whether, supposing Katherine was her ancestor, she was part vampire. Damon shoots this down and says that if Katherine had any children, it was before she became a vampire.
- Most of the various immortal races in the Old World of Darkness are like this. Only the weakest 14th or 15th generation vampires in Vampire: The Masquerade can have children, who end up as dhampirs, only extremely yang-imbalanced Kindred of the East can have children (their version of dhampyrs), and that's made increasingly complicated by the fact that a female Kuei-Jin has to remain yang-imbalanced throughout the pregnancy, and demons from Demon The Fallen might possess human bodies, but they lack the spark of life to create true progeny.
- The original mummies were sterile too. However, their successors, the mummies of Mummy The Resurrection, are fertile, capable of having mortal children (justified, as the mummies' immortality is the result of the Spell of Life).
- It carries over into the new version; a vampire can only give birth to a Dampyr through the use of certain dark rituals and curses, and the True Fae of Changeling: The Lost are described as immortal, all-powerful, and utterly sterile. That is, until you find out that the titular changelings risk becoming True Fae if they hit Wyrd 10 and Clarity 0 — which means their abduction/Mind Rape was the reproductive cycle.
- In Dungeons & Dragons, the lifespan of elves has decreased somewhat over the various editions (from a maximum of two thousand years for grey elves in 1st edition to a handful of centuries now); perhaps this is appropriate, considering that they've become more and more common in their game worlds, suggesting higher levels of procreation. Okay, fine, they're still supposed to be majestic, long-lived, and rare, but Rule of Cool sometimes dictates otherwise.
- They say now that Elves do reproduce, but it's a long pregnancy, and that they need to wait 5 years to get pregnant again.
- Another example is the 3.5 edition Elan, a race of psionically enhanced and modified humans who are functionally immortal. They can no longer procreate with humans due to their modifications (they are classified as aberrations, not humanoids), and the only way to make more Elans is by modifying an existing human with a mixture of psionics and an alchemical conversion process.
- In Warhammer 40,000, the same procedure that turns humans into near-immortal, superhuman Space Marines also renders them sterile.
- Possibly it could just be a result of the degeneration inherent in certain chapters' methods or traditions. The Salamanders chapter is known to raise families of their own, and the Space Wolves are renowned for their, ahem, voracious appetites when it comes to the pleasures of the flesh. But most chapters do indeed not have children, whether because the process that made them Space Marines is corrupt or they are simply forbidden is left up in the air, which, given Warhammer 40,000 canon, is completely intentional.
- Most likely Space Marines remove their... umm, you know.
- The second edition rulebook actually implied that the muscle growth accompanying the change into a Space Marine caused one's scrotum to be absorbed by the growing thigh and abdominal muscles. That particular trivia has mercifully not been re-printed since.
- Space Marines are genetically and surgically modified. Even assuming that they are fertile (seems unlikely) and not poisonous, the children wouldn't be Space Marines, and might not be normal humans either.
- Space Marines are largely infertile for three reasons. One, the God Emperor of Mankind did not want a race of immortal super warriors to replace mankind, but to defend it. Thus there are no female space marines and those that presumably can breed just produce regular humans. The second reason is that their extensive genetic and surgical alterations completely change much of their bodies structure. Since preserving reproductive capabilities is low on the list of priorities for the transition process, most marines likely do come out sterile. The third reason is that marines devote themselves entirely to war, they are either fighting, training to fight, or praying. Marines are only mandated 30 minutes of free time a day, and many chapters don't allow even that. Few chapters give a marine the chance to even find out if they're fertile, rendering the question of their fertility irrelevant.
- Similarly, the Eldar combine a low birth rate with a natural aversion towards any sort of extreme emotion (an Eldar having sex is practically begging to get his soul sucked out by Slaanesh), to the point where their population is likely just below sustainability levels.
- Played with the Dark Eldar. They can indeed reproduce, but the majority of Dark Eldar are vat-grown clones (which serve as mooks in combat or spare bodies in experiments) which are only sub-par (allegedly) in combat skill but otherwise differ little from actual Dark Eldar. Dark Eldar literally feed on pain and uses this to extend their lifespans. Asdrubael Vect, Archon of the largest Dark Eldar Cabal, is currently the oldest living being in the universe, bar the Chaos Gods and Necrons.
- Spycraft has a setting, 'World on Fire'. One faction is the Eternals, which are Exactly What It Says on the Tin. They can have children, but these are very very mundane.
- Invoked by Tzeentch in Warhammer Fantasy. The ancient race of Dragon Ogres asked the Lord of Change for a boon, to make them immortal. He did, but also rendered them sterile. Most of the still-living Dragon Ogres consider this to be Tzeench's idea of a joke.
- The Slann, the rulers of the Lizardmen, do not seem to be able to die of old age (the oldest are old enough to remember the Old Ones), but there have been no new spawnings of Slann since the disappearance of the Old Ones some eight thousand years before the present day. None of the Lizardmen species in Warhammer breeds in a sexual manner, their eggs simply come into being in magical spawning pools deep in the Lustrian jungles - each new spawning occurring according to the (now much fragmented) plan of the Old Ones. But the Old Ones didn't plan on needing more than five generations of Slann, and there is nothing the Slann themselves can do to increase their numbers, so they are now a dying race, and the loss of even one is an incalculable blow (See Warhammer: Lizardmen (2013), p. 31).
- Likewise, Warhammer's elves can live for thousands of years, but produce so few children that they are slowly declining and dying out. Warhammer's Dwarfs live for hundreds of years, and seem to breed at far below replacement levels as well. Meanwhile short-lived humans breed at human-normal rates and the rat-like Skaven, the vast majority of whom never live past twenty, breed in huge numbers like the swarms of vermin they are.
- Warhammer's Undead, including Vampires, are completely unable to reproduce. Except by raising more corpses with magic.
- In Creatures games, there are many "immortal" third-party breeds; the majority of them are infertile by default, because immortal creatures capable of breeding would overpopulate the world pretty quick.
- But the Fast Ager Norns, who tend to evolve spontaneously in many C3/DS wolfing runs, avert this. Maturing within seconds, very fertile, and immortal, they will easily max out your population no matter what population limit you choose. They're basically the cancer of the norn population.
- In the Fallout series, the two types of creature that are biologically immortal, Super Mutants and Ghouls, are both unable to reproduce. The former due to sterility as a side effect of FEV perceiving the 23 chromosomes in sex cells as "damaged" and "repairing" them by filling in the missing chromosomes, and the latter... radiation sterility and, well... rot?
- Van Buren would have had "born ghouls," children born into ghouldom. To Drs. Sebastian and Clark, the masterminds of the breeding program, the born ghouls represent the future of the ghoul "species."
- Averted in Lost Odyssey: the five immortals can and do have children, but their children, even when both parents are immortal are not themselves immortal, mainly for plot reasons. This prevents any potential overpopulation problems.
- Mass Effect
- Initially averted with the krogan. They were a species of walking tanks that gave birth in litters of over a thousand, and are functionally immortal (it's not even clear if they can die of old age). However, while their Death World homeworld kept their numbers in check, once they were colonizing more pastoral worlds, their population exploded in a single generation. To stop the Krogan Rebellions, the entire species was infected with a virus that devastates their birth rate (1 out of 1000 is live, the rest are stillborn). And even with the high mortality rate, they're still capable of maintaining a population equilibrium if not for the species wide fatalism that followed the Genophage (kind of hard to keep you chin up when your allies annihilate a fundamental aspect of your biology and society).
- The asari, who live for one thousand years, don't seem to have a problem with this trope though. They happily breed all they want to. On the other hand, in order to become pregnant, the asari has to be consciously trying to become pregnant. They can have sex all they want and only reproduce when they have a desire to. The asari, of course, are an entire race of Blue Skinned Space Babes, which probably rejiggers their place on the immortality vs. fertility continuum. Most of the time the asari don't choose to procreate before they pass their 300th birthday and become Matrons, and generally don't have that many children in their whole lifetime; nearly 1000-year old Matriarch Benezia only has one daughter, for example. Aethyta, who's as old, is implied to have had a good number, but then her father was a krogan.
- True Ancestors in Tsukihime are noted in supplementary materials to have been rather on the decline. They did not even have enough children to replace the members they lost, so the birth of Arcueid itself was pretty big news even before people knew how powerful she was. Possibly tied to the fact that they were almost entirely all male.
- In Golden Sun II, the ancient lost civilization of Lemuria has a grand total of two children, both of whom comment on how lonely it is being surrounded by ancients. (Lemurians aren't strictly immortal, but they slow down their aging process to live many centuries.)
- Averted in Dwarf Fortress, with interesting results. Elves mature and reproduce at the same rate as humans, but have no upper limit to their ages. This results in massive populations; they would have taken over the world by sheer dint of numbers if it weren't for two weaknesses: they are poorly armed (having only wooden weapons and armor) and they are cannibalistic maniacs who start wars over the way other species treat plants, resulting in them warring with pretty much all of their neighbors. Battles with thousands of elves fighting (and losing to) less than a hundred dwarves are not uncommon.
- World of Warcraft has the Draenei, who live for at least tens of thousands of years (and may be immortal), and very rarely have children.
- Also, now that Night Elves are no longer immortal (their natural lifespan is still probably pretty long, but not infinite) they're starting to have kids more, as evidenced by some of their quotes.
- Played straight and Averted in The Sims 2. Zombies and Servo robots are immortal but cannot have children, while Vampires can reproduce, but any children born will be completely normal.
- in The Sims 3 Vampires are no longer immortal (though they still live much longer then regular sims), and can have children at the same rate as ordinary Sims at least in theory although only half of their children with an ordinary Sim will be Vampires. Also, the Fairy Sims in the Supernatural expansion have the same lifespan as Vampires, and can likewise reproduce at the same rate as ordinary Sims. Both also age at the same rate as ordinary Sims until they reach adulthood.
- In RuneScape, the Dragonkin are nearly immortal, living for thousands of years at least, but can still be killed, and can't reproduce. This has lead to them becoming very afraid of death.
- The Trow in Bungie's Myth series were created as an entire species by the god Nyx at the begining of the world. They have no natural causes of death, are eighteen feet tall, and have bodies that are as tough as stone. For many thousands of years they dominated the world, but entropy and a series of costly wars took its course, and now there are only a few hundred Trow left, if that. The ones that remain tend to keep to themselves, though prey you never have to run into one on the battlefield.
- A female dwarf in Divine Divinity mentions that she is pregnant, but she's only in her tenth month, so she's not showing any visible signs yet.
- In novels for StarCraft, the Xel'Naga were incredibly long-lived but couldn't reproduce. Instead, they turned other races into more of them!
- Technically, what they tried to do was create 2 races: one to have a "perfect form" and one to have a "perfect spirit". After millennia, the two would eventually join to evolve into the next cycle of the Xel'Naga. Unfortunately, someone threw a monkey wrench in the works.
- In Aselia's ending for Eien no Aselia both she and Yuuto are Eternals and have a child together. This is apparently completely unheard of and they're a bit nervous about how they're going to explain it.
- In The Elder Scrolls, the Mer (Elven races) live considerably longer (how long is undisclosed), but have far fewer children. However, their chance of having children is higher if they have a non-elven lover, and the Bretons are an entire race of Mer/Human hybrids who eventually outbred both of their parent races in the region of High Rock.
- This is stated to have caused a major problem for the Falmer (Snow Elves) back in the First Era, since they did not breed as much as their neighbouring humans did. This caused peace to break down and the result was that the Falmer were driven to extinction or horribly mutated, bar a few hundred individuals that did indeed survive.
- In-game documents and supplemental materials for the Myst series reveal that the D'ni, whose lifespans could run into a fourth century, reproduced very slowly due to the narrow window (30 hours every 72 days) in which their women could conceive.
- In Sonic Adventure and Sonic Adventure 2's Chao Gardens, Chaos Chao are immortal, but can no longer breed.
- In the StarCraft universe, the Protoss are a very long-lived species; Artanis, at 262 Earth years old, is considered "young", while Matriarch Raszagal was 1,045 at the time of her unnatural death. They are also stated to be "not a prolific people"; even before the events of the first game, the Protoss' population was steadily declining, as they were dying of old age faster than they could bear new children. The Fall of Aiur, with the resulting tremendous fatality count, worsened the situation.
- It doesn't help that the various Protoss tribes killed each other in droves during the Aeon of Strife, only stopping after Savassan (AKA Khas, "He Who Brings Order") used Khaydarin crystals to mentally unify the race.
- Janos Audron in Legacy of Kain says "Vampires are no longer born" implying that Vampire meant a race, and the curse that caused them bloodthirst and immortality also made them sterile. They tried to preserve their line by passing the curse onto humans.
- The Manaketes of Fire Emblem live for thousands of years, and are almost all sterile. Although, it should be noted that this may have been retconned, as Awakening features three Manaketes, all fertile, and absolutely no mention of the race's sterility either way.
- As a demonstration of why this trope is often necessary, the site Grudgematch had a hilarious take on the disastrous consequences of James Bond winning immortality in the grudgematch: massive inbreeding due to James' libido.
- Elves in Tales Of MU are true immortals in terms of lifespan, and generally quite sexually potent as part of their being better than everybody. They keep their birth rate low by doing things that don't produce children.
- The alien race known as the Silent Ones in Orion's Arm use a treatment that completely halts aging but severely stunts the development of their larvae, so they keep small groups of mortals to replace the few immortals that die. However most Terragen (human-derived and/or created) sophonts are effectively immortal and decidedly not infertile, the population being in the quadrillions about 10500 years in the future.
- Word of God (pun intended) has this as being the demographic issue with the angels in The Salvation War — "angelic females simply are not very fertile and the chance of conception is extremely low," so the reason for the war being fought on Earth is to put off or prevent any human incursion into Heaven. Whereas the daemons tended to be killed ''en masse'' in generally horrible ways during the Curb-Stomp War, their birth rate will allow them to eventually recover, whereas angels dying off in those numbers might actually cause them to go extinct.
- Although as of Chapter 83, it seems that the low birth rate of the angels was at least partially due to Yahwehh's obsession with controlling sex and sexuality and now that he's been killed there's been a rash of pregnancies among the angels including Maion.
- Dissected (and arguably deconstructed) by the Writerium (and its successor the Writer's Workshop).
- This blog post hilariously suggested that romances like the one in Twilight prevent vampire from population problem.
- The eponymous AH.com Eternals can have children normally both with ephemerals and other eternals. The vast majority of these children are completely mortal though. The character of Gregorios, for example has had more than 160 children over the course of his lifetime, and only one other has proved to be an immortal so far.
- Dan and Mab's Furry Adventures :
- Cubi Clans are led by a Tri-winged Succubus or Incubus, who are as close to immortal as one can get with a an ungodly long lifespan and are so powerful very few dare to challenge them. The catch is they cannot have children of their own, and while it is possible to convert non-blood relatives to their clan there must be at least one fertile member of the clan alive who has had a child with the prospective member. The character Fa'lina shows how this can be bad, being a clan leader and being the last surviving member of said clan.
- In addition to Cubi, no new members of the Fae race may be born until living members willingly and deliberately die. They can have children with just about anything, but, well...
- Destania's clan leader Cyra is in a similar boat as Fa'lina. Destania is her last surviving "child" and she can't even speak with her anymore since Destania has given up dreaming — and Cyra mostly communicates in dreams. So she's absolutely thrilled when she gets the chance to speak with her "grandson" Dan.
- The elves of Errant Story previously had an extremely low fertility rate, which is part of the reason why taking on human lovers was so popular among them; as Sarine put it, elves could "try for centuries to have an elven child with no success, or they could go fuck a human and have the next best thing." In the wake of the Errant Wars, the elven fertility rate seems to have dropped from "low" to "zero," as the last elven child born is now some 1,500 years old.
When Meji finally starts 'talking' with Senilus, one of the things she learns is that the something went wrong when the 'gods' made one of the races; the race would lose the ability to reproduce itself after 427 generations. Since the first two races the 'gods' made weren't able to reproduce, and the last race made by the gods is generally agreed to be the trolls, it is very strongly indicated that the race in question is the elves. But they are still fertile with humans, since errant Meji is only 17, and errants can be very long-lived.
- Parodied in Irregular Webcomic!'s "Fantasy" storyline, where it's pointed out that Elven longevity also means that young Elves take centuries to grow past adolescence. As a result, the Elves invented prophylactics before they discovered how to use fire.
- The Bradicor of Ghanj-Rho in Schlock Mercenary have, individually, survived millions of years and watched the evolution of intelligent life forms, but are indifferent to the gradual extinction of their species. The heroes end up accidentally flattening their last female during first contact and dooming them to extinction. The Bradicor react more with annoyance than anything else seeing how they were already sterile.
- In Jack there are some people who have missed their chance to die for some reason, their biology is frozen at the point where they should have died and they can't reproduce as a result. And it appears that sterile immortality was intentional.
- Drowtales plays with this, in that drow are The Agelessnote but some, including Ash'waren and Zala'ess, are known for their extremely large families, but they tend to be the outliers on the far end of the scale. Meanwhile Diva'ratrika Val'Sharen is over a thousand and has only had five (surviving) daughters and one son, which the suggestion that politics has played a role in this. Meanwhile, during a 15 year timeskip, Mel'arnach has three children, which suggests fae are able to have multiple kids within a short amount of time with relatively little trouble, and drow in particular elevate motherhood to a sacred level, with one character's losing her ability to have more children playing a critical role in her motivations and actions. The Crapsack World nature of the environment means that despite people having lots of kids the population has stayed relatively stable due to the high chance of death.
- The Enchanters in At Arm's Length are fully capable of having children at any time, but social norms tend to prevent this. Also, the biological clock normally doesn’t start ticking until a few millennia, eliminating the desire to have children for quite a while. Enchanters who have children while they’re still relatively young, or have more then one, are typically frowned upon.
- In El Goonish Shive, Immortals are capable of having children, at least to some degree. Most do not seem to do so, though. "Half-Immortals" (called "elves" in the series jargon), the offspring of an Immortal and an ordinary human, are confirmed to be sterile. No word on what happens if two Immortals attempt procreation.
- My Little Pony: Friendship Is Magic:
- Celestia and Luna seem to follow this trope. They have both lived at least a thousand years, possibly much longer, and their only onscreen relatives are a niece and a nephew (and presumably their offscreen relatives). The existence of Age spells only accessible to really powerful unicorns further complicates things, as their immortality may not even be natural.
- However the real reason seems to be they just don't have a husband.
- Dragons are capable of producing offspring, though the rate at which they do is not established and one can assume they follow the rule of longetivity as most dragons do.
- Fairies in The Fairly Oddparents are forbidden to have children, mostly because A) they're immortal and don't really need to, B) A newborn fairy's Reality Warper powers are dangerously unstable and C) the last one born was Cosmo. The only reason Poof exists is that no one forbade their godchildren from wishing for them.
- More accurately, Jorgen keeps forgetting to implement that rule, so it's possible that there may have been more Fairy babies brought into life (explaining Poof's peers in nursery school.) Poof seems to be a big case because of whom his parents and godbrother is.
- Crystal Gems in Steven Universe don't age, but Rose is the only one known to have had a child (Steven), which resulted in her child being born with her gem. Word of God states that Crystal Gems don't normally reproduce at all, and whatever Rose did was extremely out of the ordinary. Rose even stated in her Video Will that her and Steven can't exist at the same time, and she's becoming (half of) him as much as she's giving birth to him.
- The situation turns out to be more complicated. Gems don't (usually) have children the way that humans do, but they have a quite effective, albeit destructive, method of producing more Gems. The Homeworld Gems using earth to create more Gems is actually what caused the Crystal Gems to side against them.
- Averted with amoebae, and other single celled organisms that reproduce by binary fission. When you split in half (as opposed to budding off a daughter cell), you can consider both resulting amoebae to be an extension of the life of the parent. In short, every single amoeba on the planet is the very first amoeba. They're immortal and reproduce like crazy. Good thing they're fairly low on the food chain, so their hypothetical immortality isn't much of a problem.
- Throughout history people have attempted to discover the secret to eternal life and Audrey De Grey is probably the most famous example in modern science. He has come up with his own theories and has even gone so far as to speculate that once humanity has stopped, and reversed, the ageing process; people will have to file a form to have children and then wait for other people to die (through natural causes or requested suicide) to be given the go ahead.
- Thought experiments on population growth rates suggest that extending lifespan needn't necessarily produce an Explosive Breeder, as it's really the age at first reproduction that determines how fast a population grows. Mathematically, having a breeding female live forever will do less to increase birth rates than having her produce a daughter (who'll breed early in turn) slightly sooner.
- This idea is truth in television in human communities insomuch as the childbirth rate of a country appears to be inversely proportional to its average lifespan. This is attributed to things like education, not seeing everyone around you die young (which tends to cause survivor lust), and good healthcare that improves lifespans and reduces infant mortality, meaning people don't need to have as many children to guarantee some survive. More developed countries also tend to have less of a primary-industry focus meaning children are a net drain on assets rather than a source of income. State welfare and wealth in general also means parents aren't as reliant on children to support them in their old age.
- Because human oocytes (eggs) are produced by a woman's ovaries before she, herself, is born, an immortal woman's capacity for natural reproduction would inevitably expire when her supply runs out, even if she never goes through menopause (assuming the science at some point won't be able to reboot the ova production mechanism, of course). She could, however, give birth to a baby conceived in vitro from a donor egg.
- This has recently been Jossed by the discovery of egg-producing stem cells (so-called oogonial stem cells) in adult women's ovaries. Regardless of this, menopause obviously still renders women infertile.
- There are also services now that preserve a woman's egg in case she doesn't end up having a baby until after menopause. This is the same as the process mentioned above with the only difference is that it's still her own baby.
- The immortal jellyfish doesn't die; it turns back into a baby and starts over. A total aversion because it also reproduces quickly.note