So the DepopulationBomb has dropped, usually in the form of a highly selective virus or bacteria that is only fatal for adults, leaving the kids to inherit the world. Frequently seen in AfterTheEnd fictions, OnlyFatalToAdults has two variations: In the first, death strikes at the onset of puberty, killing only the sexually mature. In the second, the highly selective agent of the Depopulation Bomb kills in the late teens or in early adulthood, killing only the socially mature.

Another important distinction is whether the DepopulationBomb is only a concern that one time, or if it will begin to affect the kids when they grow up.

Due to the difficulty in convincingly presenting a hypothetical weapon with such specific depopulation capabilities (especially if in the second form, where the bomb seems able to detect a set of legal and social traditions that are only very loosely connected to biological changes), a popular form of this is to have a non-discriminating apocalypse wipe out mankind in general, then re-populate the planet, say, sixteen years later, with a bunch of infants who were locked away in a survival shelter at the time.

If the Depopulation Bomb is OnlyFatalToAdults, then this trope justifies ParentalAbandonment. It also justifies storylines in which children and teens have to [[PromotionToParent take on the responsibilities of adults]], or form extended families of their own in order to survive. Can also justify TeensAreMonsters if [[TeenageWasteland teens survive and are left to fend for themselves]]. In some variations, due to the ages of the characters and the intended audience, guns are rare and the NerfArm is ubiquitous. [[FamilyFriendlyFirearms Sometimes, there are even lasers]].

This will pretty much always lead to a TeenageWasteland. Compare {{Gendercide}}. Also see InfantImmortality.

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!!Examples:

[[foldercontrol]]

[[folder:Comic Books]]
* TheDCU miniseries ''WorldWithoutGrownups'' had all the adults spontaneously disappear from the face of the earth. Robin, Superboy, and Impulse had to get everything together if humanity was to be saved, leading directly to their formation of ComicBook/YoungJustice.
** Natually, the [[{{Diniverse}} DCAU]] provided its own spin in the ''JusticeLeagueUnlimited'' episode "Kid Stuff", where Mordred banishes all the adults from Earth, and Superman, Batman, Wonder Woman, and Green Lantern have to get turned into preteens to go back and stop him.
* In the Pre-Crisis Earth-1 {{Superman}} continuity, Superman's adoptive parents, Jonathan and Martha Kent, died after contracting a virus that only affected adults. Superman was still Superboy at the time, so the virus did not affect him. Several years later, Lois Lane and Lana Lang contract the same virus and almost die before the now adult Superman realizes that the virus entered his body as well, and his body created anti-bodies to counteract it.
* "Kids Rule OK", a strip in 70's British comic ComicBook/{{Action}}. The vast majority of adults die, leaving only rampaging gangs of kids that start to beat seven kinds of crap out of each other. Until the comic fell foul of Moral Guardians and they all make peace after being given a [[http://www.sevenpennynightmare.co.uk/stories/strips/kids.htm Stern Talking To]].
* One ''ComicBook/{{Hellblazer}}'' mini-arc features John Constantine's niece being enlisted to travel to an island where a group of [[UndeadChild Vampire Children]] all under the age of 13 who attack any adults that come near the island, but don't harm other children.
[[/folder]]

[[folder:Fan Fiction]]
* This kind of thing seems to happen once a week in the universe of premier MarySue FanFic/MarissaPicard, where Stephen Ratliff uses this kind of stuff to justify regularly allowing his Kids Crew protagonists to have command of starships, starbases, entire systems, etc.... One story in particular had a group of hijackers use a sleeping gas that only affected adults for no apparent reason beyond this.
* ''Fanfic/EigaSentaiScanranger'' had a MonsterOfTheWeek armed with poison that dehydrates anyone who touches it/drinks it, but only if they're over 25. It's unclear why that was brought up when what wasn't brought up was what the villains hoped to accomplish. The poison would only work on one of the six rangers, for crying out loud.
* In ''[[Fanfic/DayOfTheBarneyTrilogy Day of the Barney]]'' everyone over the age of thirteen disappears. And by "disappears", I mean Barney brainwashes all the younger children to slaughter them en masse before joining their purple friend in happy fun-fun time forever. And when they reach the age of thirten, ''they get to go on a vacation''...
* [[ThePlague A plague]] of this nature takes out nearly all the adult Smurfs in Papa Smurf's generation, leaving him as the only parent figure of a hundred young Smurfs in ''Fanfic/EmpathTheLuckiestSmurf''.
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[[folder:Films -- Live-Action]]
* The 1972 cult film ''Gas-s-s-s'', where an industrial accident releases a poison gas that kills everyone on earth over the age of 25. In the rest of the film, the main characters have to learn to survive on their own. The concept is laden with FridgeLogic: the gas was designed for use in TheVietnamWar, but the average age of a soldier in 'Nam was ''19''. [[FridgeBrilliance Maybe it just didn't work right?]]
* Inverted in ''Clive Barker's The Plague'', in which every child on Earth under the age of nine suddenly falls into a coma, and every baby born in the next ten years is also born comatose.
* "Night of the Comet" has elements of this. The survivors are teens because [[spoiler: the few people we see who were properly shielded just happened to be in that age group, while nearly the whole planetary population were out watching the sky.]] Probably some adults survived aboard submarines and other suitable places. One wonders about the other side of the planet.
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[[folder:Literature]]
* In the novel ''Worlds Apart'' by Creator/JoeHaldeman (second book of his ''Worlds'' trilogy), Earth has been devastated by the second type. He ties the disease to when the body reduces production of human growth hormone. So there are some adults around because they suffer from acromegaly, a disease where adults produce too much human growth hormone.
* This was the premise for ''Literature/ShadesChildren'' by Garth Nix. Except here the world is run by evil overlords who chop up anyone over 14 for body parts. When they took over, though, everyone over 14 instantly disappeared and beyond this being the fault of the overlords it's never completely explained.
* In ''TheSubtleKnife'', the second book of the ''HisDarkMaterials'' trilogy, there's a world in which there are soul-eating 'spectres' that only target adults. At one point the heroes are in a city only occupied by children, although it turns out that most of the adults left, rather than being caught by the spectres, and will return once the spectres move on.
* The plot of the BlakeAndMortimer book ''TheVoronovPlot'' revolved around a virus recovered by a KGB scientist from a crashed Soviet satellite which was only lethal to adults. The scientist, Dr. Voronov, a Stalin admirer, planned to use the virus to overthrow the Soviet Union and conquer the West. Late in the book, he starts using the virus in a [[MoralEventHorizon particularly despicable fashion]]: [[spoiler: he acquires a network of contacts in the West all with small children who are injected with the virus. Afterwards, the parents send the infected children near key political figures who under their orders, innocently ask them if they can kiss them on the cheek. Not suspecting an innocent child, they accept... Only to die a few hours later.]]
* The children's book ''Literature/TheGirlWhoOwnedACity''. The set 'death age' here was twelve, and most of the adults knew about it before they died.
* This is most of the plot of Literature/TheFireUsTrilogy. A band of young children are living on their own, but eventually find a group of religious zealots who go so far as to name themselves after various religious passages.
** [[spoiler:In fact, it turns out that the zealots are responsible for the virus, so as to more easily find the Second Coming.]]
** The kids also find a group of elderly women in a retirement home, that survived only because post-menopausal women were the only adults that weren't affected by the virus.
* An interesting variation: In Creator/LarryNiven's ''Literature/AWorldOutOfTime'', only pre-adolescents can use the immortality treatment and cease aging, while those who pass puberty become immune to the treatment and age and die normally. Rediscovering an immortality treatment usable by adults and breaking the status quo of the immortal children's hegemony forms a large part of the book's second half.
* In Creator/DavidWeber's ''Literature/HonorHarrington'', people can get a treatment that will double or triple their lifespans, but only while they're still young. There are three levels of effectiveness. First generation Prolong can be performed as late as 25. Second generation treatment is only effective into the early teens, but gains a century or so more; Third generation, it is implied, will extend life even more effectively (it's very new, so the first people to get it haven't grown old yet), but requires genetic manipulation even before the recipient's birth..
** Availability of Prolong is the single biggest quality of life difference between various worlds. For instance, it becomes a plot point that the Kingdom of Manticore is welcomed in an area they annex simply because Prolong had not previously been available there, save to the very rich, but the Manticoran public health system guarantees it to all.
* The post-apocalyptic young adult novel series ''{{Countdown}}'' began with the release of a deadly virus that somehow turned everyone but young adults into black goo.
* Inverted in the ''LeftBehind'' series - in addition to righteous people in general, all children under an unspecified age are CaughtUpInTheRapture. Presumably this would be [[JustifiedTrope justified]] by means of ChildrenAreInnocent.
** Except that any denomination that believes in the original sin sees babies as inherently sinful.
*** Except that many denominations that believe in original sin also believe in the Age of Accountability, which denotes that age at which a person becomes mature enough to be held responsible by God for his or her sins.
* The premise of the book series ''Literature/{{Gone}}''. All people over the age of 15 disappear one day, and continue to disappear throughout the book, i.e once one turns 15, they vanish. [[spoiler: At the end of the first book, Sam and Caine figure out how to avoid disappearing. They later tell the other kids, giving them a choice of staying in the FAYZ or "stepping out" when they turn 15.]]
* OnlyFatalToAdults is combined with {{Gendercide}} in the backstory to GeorgeRRMartin's first novel ''Dying of the Light''. Part of what has shaped the Kavalan culture is a biological weapon that kills any sexually mature woman.
* In the novel ''Literature/{{Idlewild}}'' by Nick Sagan (Carl Sagan's son) [[spoiler: a group of teens live in a virtual boarding school. It turns out that every human on Earth was wiped out by a disease. The kids were genetically engineered to be immune to the disease, and just before the end of civilization were placed in vaults and connected to a virtual world to be raised. Through the course of their virtual lives they are educated and trained in professions that will help them rebuild society. They were aware that the boarding school that they attended was virtual, but didn't know that the rest of their lives were also virtual. Needless to say it comes as a shock that everywhere they've ever been and everyone that they've ever known, their families and friends (except the few that attend their school), are all simulations.]]
* In LordOfTheFlies the plane crash in the beginning kills all of the adults on board leaving the children to fend for themselves.
* In Chris Adrian's book ''The Children's Hospital,'' all the adults [[spoiler: except Ishmael]] die of the strange dust disease; [[spoiler: protagonist Jemma is the last to die, and dies as Ishmael leads the now-awake children out of the hospital and onto the new world.]]
* The ''Reapers'' trilogy by Andrew Butcher relies on this trope: everyone over 18 dies of the mysterious Sickness, leaving the protagonists to fend for themselves. It turns out [[spoiler: it was a bunch of alien invaders who want to take Earth's children as slaves.]]
* Donaya Haymond's [[Literature/LegendsOfLaconia Waking Echoes]] has The Famine Fever, which is Only Fatal To Adults And Children, sparing the adolescents alone. [[spoiler: This is because [[AWizardDidIt the Creator God of the dimension did it]] as a Biblical-style scourge. The adults could be judged by their deeds and the children were innocent, but the youths required further testing.]]
* The GentlemanBastard series has Black Whisper, a plague that typically gives anyone who hasn't entered puberty a case of the sniffles and everyone who's entered or completed it a case of screaming death. An outbreak in one particular district is what makes protagonist Locke Lamora an orphan at a young age.
* Lauren Destefano's in-the-works series [[TheChemicalGardenTrilogy The Chemical Garden]] deals with genetically modified persons. The women all die at age twenty, and the men all die at age twenty-five.
* The Young Adult novel ''Starters'', by Lissa Price, is set in a post-war {{dystopia}} where only the very old and the very young survive. The young can temporarily 'rent out' their bodies so the elderly can enjoy a virtual youth.
* "The Underdweller" by William F. Nolan has the world populated by children because [[spoiler: aliens massacred all the adults to break the continuity of human civilization without actually destroying the species]], or so the protagonist theorizes. He survived because [[spoiler: he was in a sewer tunnel where the rays didn't reach.]]
* In [[Literature/TheBible the Biblical]] Literature/BookOfExodus, only those under 20 make it to the Promised Land. Those who are older than 20 were wiped out by various means as a result of their complaining...and the fact that they were a RagtagBunchOfMisfits wandering around the desert for 40 years. Even Moses doesn't make it in.
* ''Neptune's Children'' By Bonnie Dobkin is this,with the kids trapped in an amusement park.
[[/folder]]

[[folder:Live-Action TV]]
* ''Series/StarTrekTheOriginalSeries'' had a planet that was an exact duplicate of Earth (amazing!) in the episode "Miri", on which the only survivors of a mysterious plague were a band of savage children. Their childhoods lasted centuries, but they were doomed to die at the onset of puberty.
** The ''Series/StarTrekDeepSpaceNine'' episode "Quickening" features a planet where everybody is struck with plague that is present from birth, but usually only kicks off in adult age, killing the victim. This is then turned UpToEleven when Bashir cannot cure the plague, but procures a ''prenatal'' vaccine (every baby whose mother received it through pregnancy will be plague-free).
* The TV series ''Series/{{Jeremiah}}'' took place fifteen years after a plague wiped out anyone over puberty. [[spoiler:It's later revealed that the plague was a synthetic bio-weapon which was designed this way as a "mercy weapon," to kill anyone in the targeted area old enough to fight back, but "sparing" the children whose parents you just killed. It got out of control and destroyed the world.]]
* The Kiwi teen soap ''Series/TheTribe'' has this as its backstory: a mysterious virus kills basically everyone over 18 or 21 and the kids and teens are left to fend for themselves. The show was half teen soap and half CozyCatastrophe, and [[FamilyFriendlyFirearms there were even lasers with stun settings]]. All it was missing was that ''Literature/AClockworkOrange'' element of graphic, violent, badassness to make it [[DarkerAndEdgier realistic and gritty]], but it tried.
** Still, there was that heartwrenching intro...
*** "Authorities are appealing for calm throughout the evacuation process..."
* The ''Series/StargateAtlantis'' episode "Childhood's End" (unrelated to the ArthurCClarke novel) involved a village where everyone committed ritual suicide after reaching a certain age, because they thought it was required to protect them from the Wraith. In truth, the Ancients set up an EMP field that incapacitated any technology straying into it and if the population grows too large, they will leave the field and get culled. Hence the suicides.
* This is apparently the background story for ''MST3K'' veteran ''CityLimits'', set in a post-apocalyptic TeenageWasteland. James Earl Jones escaped the effect because, well, ''James Earl Jones''!
* Japanese TV series ''BokuraNoYuuki'', is a ''LordOfTheFlies'' reminiscent story of the latter case, where a microbe kills anyone 20 and older. They fortunately came up with convincing enough sounding AppliedPhlebotinum to justify it.
* The world of ''2030 CE'' is plagued with Progressive Aging Syndrome, a disease that causes rapid aging and eventually death by a person's 30th Birthday.
* An episode of ''Series/{{Andromeda}}'' centered around a LostColony of Commonwealth children, who, due to years Voltarium exposure would cause them to die by adulthood. It's not so much only fatal to adults so much as 20 years of radiation exposure with no radiation treatments kills you.
[[/folder]]

[[folder:Tabletop Games]]
* The Carbon Plague in ''Cybergeneration'' uses this trope. At first, everyone who catches it dies. First kids start surviving it, then adults do. Some of the kids that survive it come out a [[StockSuperpowers little different.]] It's much less of a DepopulationBomb than other instances of the trope. The death toll is around 5% of the world's population. Possibly a subversion: fear over the Carbon Plague allows the U.S. MegaCorps to found the [[OneNationUnderCopyright Incorporated States of America]] and children are now demonized and feared with less political power or autonomy than before. Of course, the ability to [[ShapeshifterWeapon turn your arms into guns]] might be a relevant tradeoff there.
* In TabletopRPG ''BlissStage'', the Bliss only affects humans who are eighteen years or older. This means that everyone under eighteen is safe, but only until their eighteenth birthday...
* The Dark Eldar in ''TabletopGame/{{Warhammer 40000}}'' got started when the birth of a new Chaos God turned out like this. Mix with TeensAreMonsters and serve for ten thousand horrifying years.
* The Vitusdance in {{Engel}} killed off every adult in the world. And it happened more than once. No wonder that centuries from now Earth has managed to rebuild itself into a feudal level society.
* Non-plague example: In the domain of Odaire in {{Ravenloft}}, the living puppet Maligno murdered all the adults except his creator, leaving the children to fend for themselves.
* The Plague in [[http://www.indarkalleys.com/!KidWorld/index.htm KidWorld]] only kills adults or, failing that, renders them blind. Everyone in the world still carries it though, so the eyesight of a teenager will get progressively worse as he/she grows up until it is lost altogether.
* The Miry Virus in [[D20Modern D20 Apocalypse]]. It often bypasses children altogether (having a saving throw DC of 5 + target's age).
[[/folder]]

[[folder:Videogames]]
* At the beginning of ''[[SuperMarioBros Yoshi's Story]]''. Baby Bowser transforms Yoshi's Island into a figure book, and all the Yoshis become zombie-like (not dangerous, just zoned out and miserable). The only ones that weren't affected were a couple of Yoshi eggs that later hatched and took on Baby Bowser.
* Inverted in ''AdvanceWars: Days of Ruin''. The Creeper only infects people under the age of 20/21...[[spoiler:...At first.]]
* In ''FinalFantasyVI'', Kefka's death ray claims everyone over 18 in Mobliz. There is no evidence that any children died with them. It's unclear whether this was coincidence, Kefka messing with them, or some kind of HeroicSacrifice on the part of the adults.
* A somewhat more indirect version explains the existence of Little Lamplight in ''VideoGame/{{Fallout 3}}''. The kids were on a field trip when the bombs fell, the adults all died searching the wastes, and the Vault 87 dwellers wouldn't let the kids in [[spoiler: thereby sparing them from being turned into Super Mutants by Vault-Tec's evil experiments, but the kids don't know that.]] The kids' distaste for adults became tradition; any Lamplighter who turns 16 gets forced out and sent across the Wastes to "Big Town", which considering the state of the place [[spoiler: at least until the player shows up]] is effectively this trope.
** Reading some of those diary entries, it was hard not to see something a bit more sinister in the way those kids were treated.
** The design document for Vault 29 in the canceled Van Buren plays in this trope---families were selected for the Vault, but everyone older than 15 was either turned away or redirected to another Vault in the chaos. A sentient supercomputer was to raise the kids.
[[/folder]]

[[folder:Webcomics]]
* In ''TalesOfTheQuestor'', an ancient elf king wished for eternal youth for his people. [[BeCarefulWhatYouWishFor He got it:]] Elves now die around age 20 ("Just old enough to make more elves") - which more or less caused the collapse of their society and left the surviors living as thieves and scavengers.
** Also, there have been references to "the Crimson Plague" or "the Scarlet Plague," which according to WordOfGod decimated the Racconan population on at least two occasions, killing the very old and very young--- the main reason that, despite being a long-lived race, the current population of Antillia has very few extremely old Racconans, and very few families with multiple children....
[[/folder]]

[[folder:Web Originals]]
* ''LostBoysOfTheCascades'' is a web-published story about children struggling to survive after a pandemic killed all the adults.
[[/folder]]

[[folder:Western Animation]]
* A LighterAndSofter variation happens in ''LloydInSpace'', where a space cloud merely paralyses adults rather than kills them, while kids and teens are unaffected.
* PlayedWith on ''WesternAnimation/YoungJustice:'' five powerful magic users cast a spell that makes every adult on the planet disappear. However, halfway through the episode it's revealed that they actually split the world in two dimensions--from the adults' perspective, every ''child'' in the world under 18 just vanished. Meanwhile [[{{Shazam}} Captain Marvel]], who can switch from a kid to an adult, shifts between worlds when he transforms, coordinating the effort to fuse the worlds back into one.
** It actually takes idealistic ''and'' cynical approaches to such an event. The kids' dimension is portrayed as fairly stable, with the older kids looking after the younger ones and waiting patiently for the heroes to save the day. The adults' dimension suffers widespread rioting and panic, though some of this was made worse by [[BigBadEnsemble the Light's]] interference.
[[/folder]]

[[folder:Real Life]]
* Many common childhood illnesses can be quite serious if caught as adults, and could lead to ''severe'' complications for the fetus if caught while pregnant.
** The ''Varicella zoster'' virus (aka Chicken pox), while mostly harmless to children, can be fatal if contracted in adulthood, which is why parents often try to get their children infected while they're still young so they can develop immunity. Since there are still minor risks in childhood (approximately the same risks one would have from a case of the flu, plus the obvious danger of passing on the virus to a non-immune adult), the recent development of a vaccine has been quite welcome. And if that's not enough, even if you get it as a child it can turn up again when you're adult in the much more uncomfortable form of Herpes Zoster (shingles).
** The same reasoning (and infection attempts) are often applied to Rubella (aka German measles), at least for young girls. In children, it's unpleasant but mostly harmless - in pregnant women, it is [[SeriousBusiness extremely serious]], able to blind or kill the fetus.
** Mumps, while not usually fatal, is much more unpleasant to adults than children. It's actually known to sometimes cause sterility in adult men due to severe inflammation and swelling of the testes.
* Most in-house pesticides work in this manner, killing only the adult insects. A second "bug bomb" is set off a week or so later to get any that were still in eggs.
* Huntington's chorea only becomes noticeable in adulthood (the exact age varies, but it often only manifests after the carrier has had children).
** Huntington's chorea is also terrifying with a dose of ParanoiaFuel thrown in. It's fatal in 100% of cases, generally between ages 40 and 50. It's also a dominant genetic disorder, so when you see your parent wasting away from it, you know there's a 50% chance that that'll be you in 25 years, and the same probability applies to each of your siblings. So, do you get tested and know for sure whether you have the gene, or remain ignorant until you're in your 40's and the symptoms either do or don't appear? If you do test positive, do you have children anyway or resign yourself to dying childless in order to avoid passing on the gene?
* According to TheOtherWiki, the people killed in the 1918 influenza pandemic were mostly otherwise healthy young adults. This was due to a phenomenon known as a [[http://en.wikipedia.org/wiki/Cytokine_storm Cytokine Storm]], where the body's immune system is sent into overdrive. The very young and old were relatively unaffected, due to their less robust immune systems, which reduced the damage that could be done.
[[/folder]]

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