People procreate. [[MassiveNumberedSiblings Some do it a lot.]] [[MyBiologicalClockIsTicking Some really want to do it before time runs out.]] [[ChildHater Some don't want to do it at all.]]

Yet, in fiction, people only procreate if it's relevant to the plot, and that includes {{Backstory}}. Some characters just don't seem to have siblings, and authors use this for every reason between heightening the angst of ParentalAbandonment to excusing romance {{Genre Blind}}ness. This applies even moreso in adoptive families-- parents rarely adopt more than one child in fictionland, nor have both adopted and biological children unless the plot calls for it.

In a WorldOfNoGrandparents, all parents are also only children, which means no one can raise orphans except butlers, strangers or the school of hard knocks. The orphan in question usually is also an only child.

In shojo romances, the PluckyGirl heroine has seemingly avoided all interaction with the opposite sex until meeting the TroubledButCute school bully. PluckyGirl doesn't have any brothers, and if she does, they are either too young to provide any model of what she is dealing with or they are far older and are in the parenting role, thus they also don't count.

{{The Chosen One}}s, [[LastOfHisKind Last of Their Kind]] and other such fulfillers of ancient prophecies not only suffer from Only Child Syndrome, their entire heritage suffers from it. When a man curses a family's name or [[SinsOfOurFathers goes after descendants for revenge]], don't be surprised if 100, 200, 1000 years later, [[SingleLineOfDescent there is only one descendant]]. All generations previous must have felt bad for the eventual fate of TheHero and only had one child each to make the revenge short. Presumably in a more realistic story, if being the descendant of some ancient ruler means that one has a right to the throne, for every FarmBoy who becomes king, there are 373 cousins who MissedTheCall. One wonders how they feel about this.

Most examples of ParentalAbandonment in a WorldOfNoGrandparents also features Only Child Syndrome. Oh, the {{Wangst}}.

Expect some people with Only Child Syndrome to have a few subtleties. Such as, for example, most people who can point out Only Child Syndrome in RealLife can say an Only Child is often used to never having to compete with anyone else for parental attention, or feeling like they're the only person against the world. Or even a subtle disrespect or having never truly learned to live or communicate (in the worst cases) with others their age. This is in spite of the fact that it has been repeatedly shown in scientific studies that there is not a measurable difference in the personalities of only children as compared to siblings (at least not most of the time - there're a lot of perfectionists in the only child world). Sometimes this also happens with MiddleChildSyndrome, too. Only children also tend to mature faster.

Some stories use HaremGenre situations to replace the character's lack of a family. [[BigBrotherAttraction Fans may convert a sibling complex onto characters]], since siblings are so damn rare. Either for that reason or to explain away attachments for {{Shipping}}'s sake; the unwanted girl doesn't ''always'' have to [[DieForOurShip die for the ship]].

Contrast MiddleChildSyndrome.

----
!!Examples:

[[foldercontrol]]

[[folder: Anime and Manga ]]

* Averted in ''Manga/BlackJack''. You would think that an AntiHero Doctor with notable ParentalAbandonment issues would be an only child, right? Well... no, actually. He has a half-sister from his father's second marriage. They just don't keep in touch because she doesn't like him very much.
* In ''IchigoMashimaro'', Matsuri and Miu are the only ones who are ''explicitly'' only children; Nobue and Chika are, of course, sisters, and Ana... well, who knows? In episode 16, Nobue mentions this in connection with Matsuri's parents knowing to get her the new ''Literature/HarryPotter'' book. In episode 22, Nobue reflects on why Miu often feels left out.
* Justified in ''Manga/JoJosBizarreAdventure'' - Dio (or another vampire, in the case of George Joestar) tends to take out one of the latest Joestar/Kujo's parents after the first child.
* Every mermaid in ''MermaidMelodyPichiPichiPitch'' is either an only child, or they're all sisters. Because most of the other races are off doing their own thing and mermaids have a thing about not revealing their identity to humans, the only way that most of them reproduce is by having their [[MineralMacGuffin pearl]] create a new mermaid when they die. Caren and Noel refer to themselves as NonIdenticalTwins despite never even having met before the story starts just because they were born two minutes apart, and some of the songs refer to Aqua Regina as a symbolic "mother", but the FridgeLogic says they must all be only children.
* Of the 12 Konoha genin in ''Manga/{{Naruto}}'', only Kiba, Sasuke, and Hinata have any siblings, and then it's only one (an older sister, an older brother, and a younger sister respectively), while Gaara, Kankuro, and Temari are all siblings. A strange occurrence, considering that their clans are supposed to produce [[ChildSoldiers new soldiers]] to defend their ''entire'' nation. Of course, we know nothing about the family life of many of them, and there is a high number of [[ParentalAbandonment dead parents]] so it's likely a lot of them didn't even have the ''chance'' to have many kids.
* The Sailor Soldiers of ''SailorMoon''. Usagi has an AnnoyingYoungerSibling... and that's it, she's the only one with any siblings whatsoever.
** Also, it's flat-out stated at the end of the series that Neo Queen Serenity only ever has one child in the future (Chibi Moon).
* Miaka and almost all the Suzaku Seven in ''FushigiYuugi'' have siblings, while Yui and the Seiryuu Seven (sans Amiboshi and Suboshi) were only children (we're not exactly sure about Tomo, Miboshi and Ashitare, though). However, the Suzaku Seven's siblings were either dead, killed off halfway through the story, or unimportant and thus were never mentioned. Miaka's older brother Keisuke had a minor role in the manga but played a more important role in the anime.
* This seems to be the case in MahouSenseiNegima. Of the class of 3-A, only four characters have a confirmed sibling - the Narutaki twins (each other), Makie (younger brother), and [[spoiler:Zazie (twin sister)]]. Ayaka would have had one, but he died at birth, and Natsumi has to pretend Kotaro is her little brother, but she doesn't see him this way.
** Negi has Nekane, though it is revealed she is actually his cousin. This does imply Nagi had one though, most likely an elder brother.
* In ''OnePiece'', Boa Hancock is the only major character known to have biological siblings, as it eventually is revealed Ace is Luffy's adopted brother. There are a few minor siblings like the Nyaban Brothers, the Decalvan brothers, Hotori and Kotori etc. The series does much to say that [[TrueCompanions it's not necessarily your]] [[HappilyAdopted blood that makes you family]], though.
* In ''Manga/MyBrideIsAMermaid'', [[AlwaysInClassOne Class 2-1]] has 8 cast members in it (Nagasumi, Sun, Mawari, Saru, Lunar, Class President, Kai, Akeno). Of them only Saru and Akeno have any siblings (just one each) and four are explicitly only children.
* Most lead Pretty Cures from the [[PrettyCure franchise]] are only children, with the exception of [[FutariWaPrettyCure Nagisa]] and [[FutariWaPrettyCureSplashStar Saki]]. However, [[spoiler:[[HeartcatchPrettyCure Tsubomi]] gets a newborn sister in the final episode]] and [[FreshPrettyCure Love and Setsuna]] become adopted sisters after the first half of the season. [[SuitePrettyCure Hibiki]] is actually the only lead Cure who suffers from being an only child, while [[SmilePrettyCure Miyuki]] and [[DokiDokiPrettyCure Mana]] seem to doesn't care.
** Most Pretty Cures are only children. The only Cures who have siblings are the five mentioned above, [[spoiler:[[FutariWaPrettyCure Hikari]]]], [[FutariWaPrettyCureSplashStar Mai]], [[YesPrettyCure5 Rin, Komachi]], [[FreshPrettyCure Miki]], [[spoiler:[[HeartcatchPrettyCure the whole Heartcatch Team]]]], [[SuitePrettyCure Kanade]], [[SmilePrettyCure Akane, Nao and Reika]].
*** That means on the other hand, the remaining Cures who don't have siblings are, besides the mentioned lead Cures, [[spoiler:[[FutariWaPrettyCure Honoka]]]], [[YesPrettyCure5 Urara, Karen, Kurumi]], [[FreshPrettyCure Inori]], [[spoiler:[[HeartcatchPrettyCure nobody of the Heartcatch Team]]]], [[SuitePrettyCure Ellen, Ako]], [[SmilePrettyCure Yayoi]] and [[DokiDokiPrettyCure the whole DokiDoki Team]].

[[/folder]]

[[folder: Comic Books ]]

* Franchise/{{Batman}} and all his proteges (though he adopted most of them; the various Robins seem to think of each other as brothers, [[BigBrotherMentor for better]] [[CainAndAbel or worse]]).
* Franchise/{{Superman}} is doubly so - he was the only child of the Jor-Els (though granted, they may have had more if it weren't for the [[EarthShatteringKaboom slight impediment of being dead]]), and he's the only child of his adopted parents.
* Franchise/WonderWoman's [[strike: birth]] creation into a league of immortals doesn't raise as many eyebrows as to why few children are born. Since they don't die, if they had new children showing up as often as humans do, their home island would be standing room only after a few centuries.
** Granted, Pre-Crisis Diana had a Black twin Sister. [[http://en.wikipedia.org/wiki/Nubia_(comics) No, really]].
* [[GreenArrow Oliver Queen]] and his proteges.
* An unusual number in Marvel Comics:
** Steve Rogers (Comicbook/CaptainAmerica) was an only child. [[spoiler:The Paradise-X storyline shows he just wasn't aware of an older sibling...]]
** As was his archnemesis, the Comicbook/RedSkull (probably due to his mother dying in childbirth and his father killing himself immediately afterward). Red Skull's daughter Sin is also an only child.
** Tony Stark (Comicbook/IronMan) is an only child.
** Bruce Banner (Comicbook/TheHulk) is an only child.
** Matt Murdock (Comicbook/{{Daredevil}}) is an only child.
** Peter Parker (Comicbook/{{Spider-Man}}) is an only child but justified because his parents died a short while after he was born so they didn't even have the chance to have another kid.
** All the Comicbook/{{Runaways}} are only children, but this is justified because each set of parents agreed to give their designated place in paradise to their offspring. Because there were only six places, the six couples had one child apiece. [[TheSixthRanger Victor]] is also an only child for obvious reasons. The same can't be said for Xavin and Klara, but then again, it's never been explicitly stated that they didn't have siblings back on Tarnax VII or in 1907.
** Notably averted with [[Comicbook/XMen the Guthries]]. [[MassiveNumberedSiblings All twelve of them]].
** ''ComicBook/YoungAvengers'': Hawkeye has an older sister, and it's implied that Patriot comes from a large family. Wiccan mentioned two younger siblings in the first run, but they have since failed to appear in an capacity whatsoever, so it may as well be played straight for him.
** Averted once more by ComicBook/FantasticFour; Reed Richards is the only member to be an only child. Jonny and Sue are siblings and Ben had an older brother who died when they were teens. Reed and Sue also have two children.

[[/folder]]

[[folder:Film]]

* Bootstrap Bill only had one kid in Will Turner, something that makes the plot of the first ''PiratesOfTheCaribbean'' movie.
* Anakin in ''ThePhantomMenace'' is his mother's only child.
** Though in ''AttackOfTheClones'' his mom has married, giving Anakin a stepbrother.
* From book to the first movie of ''TheSisterhoodOfTheTravelingPants'' they removed one of Tibby's younger sibling so that she only has one, Bridget's brother so that she's an only child and Lena's sister so that she can go to Greece by herself. Lena's sister who we see in the second movie must have been jealous.
* ''Film/CatchMeIfYouCan'' portrays Frank Abagnale, Jr. as an only child. In RealLife, he had three siblings.
** A background event later in the film hints that his mother has had another child, although it's not made clear if it's his half-sibling or stepsibling.

[[/folder]]

[[folder:Literature]]

* ''TheWheelOfTime'' contains a particularly {{egregious}} example. Throughout the first three volumes, Perrin never mentions any siblings and he explicitly says that he had no sisters. Then in the fourth book [[spoiler: the trollocs come in and kill his entire family, including a boatload of siblings, some of whom are indeed female. Basically, they didn't exist until they became necessary to the plot.]]
* In the ''{{Belgariad}}'', Riva Iron-Grip's family has a tendency to produce only children, due to [[BecauseDestinySaysSo divine intervention]]. Garion, at least, is only alone because his parents were killed when he was an infant. (It's implied at the end of the ''Malloreon'' that he'll break the tendency - by having one son and ''legions'' of daughters. After all, the Prophecy stated the Rivan King would have only one son. It said nothing of daughters...) ''Belgarath the Sorcerer'' lampshades this.
** In Polgara the Sorceress, it's [[{{Retcon}} stated several times]] that the line of hidden kings on occasion had multiple children (but not necessarily multiple males). Polgara presumably was only concerned with the eldest male child.
** The main line itself flows through the only survivor of the Nyissan massacre, the king's "youngest grandson." Hopefully this was a one-off and all other all-male lines are extinct. We don't need another random challenger.
* The protagonist of TamoraPierce's ''[[TortallUniverse Song of the Lioness]]'' quartet has a plot-significant [[HalfIdenticalTwins twin]], but her royal and noble supporting cast are almost all only children. In the case of Jonathan and Roger, it's explicitly for medical reasons: the Queen could bear no more children, and Roger's mother [[DeathByChildbirth died]], a condition stated to be very common. The follow-up series ''Protector of the Small'' averts this trope and has siblings up the wazoo.
* Creator/TerryPratchett and just about all of his protagonists. Though, considering how [[Literature/{{Discworld}} the Disc]] runs on narrativium, this may just be because the universe is aware of the trope. Meanwhile, Esme Weatherwax has an EvilTwin, and Tiffany Aching has about six older sisters and an AnnoyingYoungerSibling. Oh, and Mustrum Ridcully has a brother too.
** Technically all of the wizards are an eighth child of an eighth child, but Ridcully's brother is the only sibling who really comes up.
* In the ''Literature/HarryPotter'' universe out of the three main characters there is Harry, whose parents died when he was a year old, Hermione, who has no siblings and the Weasleys who are easily a case of MassiveNumberedSiblings. Then again, maybe that's why Harry and Hermione marry who they do.
** Interestingly, Hermione was supposed to have a younger sister, but [[WordOfGod Rowling wasn't able to fit her in.]]
** Death Eaters only have one child if any--just enough to satisfy plot needs: Nott, Malfoy, Crabbe, Goyle, Rosier, Mulciber, and Avery all have only one son. And these lines never go into three generations like real life would suggest. None of the original Death Eaters (Tom's era) have grandchildren in Harry's era, while none of the younger Death Eaters (Lily's era) have confirmed fathers who were Death Eaters (although there are some surnames that appear in both eras as Death Eater names).
*** Wizards live longer -- much longer -- than Muggles, though, so it may be that not enough time has passed for the third generation of Death Eater names to show, or they [[PutOnABus went to Durmstrang]], or simply attended Hogwarts during some time period between Tom's school days and Harry's and then got out of the family business.
* The majority of kids born to the characters in the ''Franchise/StarWarsExpandedUniverse'' are lone children or part of a [[UntoUsASonAndDaughterAreBorn male-female twin set]]. Wedge had two girls and Leia and Han had twins and then a boy, but they're the exceptions; for that matter, those lone children are overwhelmingly boys. Actually, a lot of ''Franchise/StarWars'' characters fit that pattern.
* In ''Literature/{{Animorphs}}'' [[StandardizedLeader Jake]] has [[GrandTheftMe Tom]], [[DarkActionGirl Rachel]] has two younger sisters and [[TokenNonhuman Ax]] has [[AlwaysSomeoneBetter Elfangor]]. The other three protagonists, over half of the humans, are only children.
** Justified in the case of Tobias, as his father [[spoiler: Elfangor]] had died, and his mom had amnesia.
* The book ''Charley'' by Jack Weyland has a typical Mormon son (except that he has no siblings) who marries an only child and together they have exactly one child.
* The only characters in ''Literature/InfernalDevices'' who aren't only children are Tessa, whose search for her brother Nate [[spoiler: who eventually betrays her, and is actually her cousin]] kicks off the plot, the Dark Sisters, Gabriel, whose siblings aren't seen until at least the second book, and Will [[spoiler: whose younger sister comes to the Institute at the end of book 2]]. Aunt Harriet, who was Tessa and Nate's mother's sister, is dead. Everyone else's parents are either [[ConvenientlyAnOrphan deceased]] or [[ParentalAbandonment simply not there]], leaving them only children.
[[/folder]]

[[folder: Live Action TV ]]

* Almost all the main characters in both ''Series/BuffyTheVampireSlayer'' and ''Series/{{Angel}}'' seem to be only children: Buffy ([[CosmicRetcon pre-Dawn]]), Xander, Willow, Cordelia, Fred, Faith, Spike and Wesley all seem to have no siblings. Only Angel (sister), Gunn (sister), Tara (brother), and Andrew (brother) are known to have had siblings - and two of those four were either already dead or were killed off straight away!
** Andrew, interestingly, originally had to keep being introduced as "Tucker's brother," even though Tucker was a [[MonsterOfTheWeek villain of the week]] who wound up being much less important to the series and only appeared in one episode.
* In ''Series/TheSarahJaneAdventures'' every protagonist is an only child including Sarah Jane herself. Her son is a special case, as he was grown in a lab by aliens.
** Sky - Luke's new adopted sister in Series 5 - has similar-though-not-matching reasoning for being an only child (biologically, anyway). On top of that, Sarah Jane's parents died when she was a baby, which justifies her lack of siblings. Meanwhile Maria's dad and Clyde's mum are divorced from partners with whom they didn't work out [[spoiler:and Clyde's dad ran off with his wife's sister, whom it's revealed he impregnated, giving Clyde an unseen half-sibling/cousin]]. The only one with no excuse whatsoever is Rani, and to be fair not all parents in the present-day want more than one child anyway.
* Nearly all companions in the new ''Series/DoctorWho'' are only children: Rose ([[spoiler: until Jackie and alt!Pete get together, but her baby brother is mentioned only once, and she's an only child for the majority of her tenure]]), Mickey, Donna, Amy, Rory, and River Song (as far as we know) are all only children. The exceptions are Martha (a brother and a sister) and technically Captain Jack (who, as it turns out, had a brother, but this fact is only revealed in his spin-off ''Series/{{Torchwood}}'').
** Adric had a brother. [[spoiler:Emphasis on had]].
* In ''SavedByTheBell'', Kelly and Slater are the only children to have siblings. Jessie does end up gaining a stepbrother. Zack, Screech, and Lisa are all only children.
* Paige Matthews of ''Series/{{Charmed}}'' grew up as an only child and when she grew up, she discovered that she had three biological half-sisters.
* Very much averted in ''TheBigBangTheory''. Howard is the only main character in the series who is explicitly stated to be an only child. Sheldon has an older brother, George, and a twin sister, Missy; Leonard has an unnamed older sister and a younger brother, Michael; Penny has an unnamed brother and sister; and Raj has a younger sister, Priya, three unnamed brothers, and another unnamed sister. Bernadette, Amy, and Stuart have an unspecified number of siblings as well. Numerous aunts, uncles, cousins, nieces, nephews, and grandparents are also mentioned throughout the series.
* Almost every ,main character on ''Series/TheVampireDiaries'' is an only child with the exception of Stefan, Damon and Matt. Caroline, Bonnie, Tyler, and Jeremy are all only child. Elena is technically an only child as well even though she grew up with Jeremy as an adopted brother (Jeremy is actually her biological first cousin)
* Almost all of the core characters on ''Series/TeenWolf'' are only children. Scott, Stiles, Allison, Lydia, Kira, and Jackson are all only children. Derek and Isaac have siblings.
* Also averted in ''{{Friends}}'': Joey has seven sisters, Rachel has two sisters, Phoebe has a twin sister and a half-brother, Monica and Ross are brother and sister, leaving Chandler as the only only-child. And that's justified seeing as parents hated each other, his Dad was gay and they [[{{ParentalNeglect}} barely noticed the son they did have.]]
* On ''{{Zoey 101}}'', Zoey is the only one of the main characters to have a sibling, her brother Dustin. Lola mentions a younger sister in passing (season three's "Surprise") who is never mentioned again and never seen, and none of the other characters seem to have siblings at all.
* This is discussed in an interesting way in ''EverybodyHatesChris''. Chris is jealous of Greg when he comes to stay with them because he's an only child and he expects all of the attention and does everything by himself, whereas Chris usually has to take care of his younger siblings. Near the end of the episode, Chris confronts Greg, and Greg says that the reason why he does everything by himself is not because he wants to, but because he has to, being an only child.
* The fact that Claire from ''Series/{{Heroes}}'' is both adopted and an aversion, having a little brother Lyle, produced vast speculation over his origins because it's so rare for a family with adopted children to have more than one.
* ''{{Smallville}}'' begins with the lonely Clark. Lex has also grown up without siblings. Lana's parents died when she was young. Pete and Chloe also appear to be without siblings. There is no reference to Kara having had any. Lois might be the one exception having grown up with a sister.
** Jimmy has a younger brother. ([[spoiler:Also named Jimmy]].)
* ''Series/{{House}}'' has the title character and as far as we know Chase, Thirteen, Taub and Kutner. It takes a while to mention Cameron's brother, Foreman's brother, Wilson's brother and Cuddy's sister.
* In ''Series/{{Degrassi}}'', the vast majority of the LoadsAndLoadsOfCharacters that have appeared over the years are only children: Snake (older brother), Liberty (younger brother), Craig (half-sister), and Holly J (older sister) are some of the few exceptions.
* Rory is her mother's only child in ''GilmoreGirls'' but that might be because Lorelai made sure she didn't have another child out of wedlock. Of course, the basic premise of the whole series is that it focuses on a mother-daughter team.
* Sabrina Spellman has many aunts, but only a couple of cousins and no siblings in ''Series/SabrinaTheTeenageWitch''.
* In an exception to the vaunted realism of ''MySoCalledLife'', five of the seven youth characters (Brian, Sharon, Rayanne, Rickie, and [[FullNameBasis Jordan Catalano]]) are only children, and the remaining two (Angela and Danielle) are each other's only sibling. These characters would have been born c. 1980, which was the beginning of the "Echo Boom", when Boomers settled down and started having families, and the birthrates rose.
* {{Series/Merlin}} zigzags the trope. At first, the core four characters (Arthur, Merlin, Gwen and Morgana) are all apparently only children. Arthur's mother died in childbirth, Merlin's father was run out of town before he ever knew he had a son, Gwen's mother is nowhere to be seen, and Morgana has a dead father and a MissingMom. [[spoiler: Arthur and Morgana are half-siblings through their father]], and Gwen has a brother named Elyan who's spent the majority of his life running around, leaving Merlin the only one without siblings.
* ''That70sShow'' had Hyde, Jackie, and Fez as only children. Eric had sister Laurie and Kelso eventually had brother Casey makean appearance, while Donna had a [[EarlyInstallmentWeirdness sister]] but was {{recon}}ned into being an only child.
* Evidently averted in MurderSheWrote, as Jessica Fletcher seems to have a different niece or nephew in almost every episode.
* ''Series/{{Carnivale}}'' provides a [[JustifiedTrope justified]] case of this, at least according to [[AllThereInTheManual the "Gospel of Knauf"]] that outlines the series' mythology. One of the pitfalls of coming from a line of historic [[TheChosenOne Avatars]] (one of the super-powered humans at the heart of the series' mythology) is that a woman is rendered infertile after giving birth to an Avatar--who, as per the rules of the universe, can only be the firstborn male child of his family. Hence, Avatars can only have older female siblings, and are very often only children.
* Most of the main characters of ''Series/{{Community}}'' seem to be only children, with the exception of Annie (younger brother), Jeff (younger half-brother), Pierce (half-brother), and Chang (brother and twin sister,[[ItMakesSenseInContext who he ate in utero]]).

[[/folder]]

[[folder: Video Games ]]
* ''VideoGame/DragonAgeOrigins'': The noble families of Ferelden are strangely small:
** The Cousland family has two children, both of them grown, and a single grandson. All of them save the elder son (and possibly the second child, one of the possible origins) are killed in the prologue. By the end of the game Fergus is the heir and sole member of the family.
** The Guerrin family consists of two brothers, one of them unmarried, and a son barred from succession because he is a ChildMage.
** Rendon Howe has three adult children: one becomes a Grey Warden and thus is unable to procreate; his only daughter has one son; and his second son is dead by the end of the game.
** Loghain Mac Tir has an only daughter, the Queen.
** Queen Anora never had any children with her husband, King Cailan, who was likewise the only son of King Maric, who was the only son of Queen Moira, who was the only daughter of King Brandel, who was the only son of King Vanedrin. And, of course, [[spoiler: Alistair]] is the last scion of the Theirin family.
** Even the minor families of Ferelden seemingly have only one or two children, and some even appear unmarried or childless. How this feudal, hereditary monarchy can survive such an impending power vacuum is never addressed. It's possible that, because this is a video game where the focus is not dynastic politics, many of these families are actually larger, or have extended, female-line branches that are simply not seen, but for a series that revels in creating a huge codex of extraneous lore, that would be a strange oversight.
[[/folder]]

[[folder:Real Life]]
* Since 1979, China's one child policy has prevented urban married couples[[labelnote:*]]With numerous exemptions, such as: you can have two kids if you live abroad, if you've divorced and remarried, or if you're an ethnic minority.[[/labelnote]] from having more than one child. This has led to coinage of the term [[http://en.wikipedia.org/wiki/Little_Emperor_Syndrome Little Emperor Syndrome]] to describe the social implications of such a phenomenon when it has an effect on a nationwide level. The multi-generational aspect of this trope is averted, however, as parents who were both only children themselves are allowed to have two children.
[[/folder]]

[[folder:Western Animation]]
* Almost all of the {{Disney Princess}}es are only children. However, in the original poem 'The Ballad of Hua Mulan', Mulan has a Younger Sister, an Elder Sister and a Little Brother ([[MythologyGag which is who they named they dog after]]) who is not old enough to join the army, but old enough to kill pigs by the time she comes home. Also, the real Pocahontas probably had many brothers and sisters as Powhatan had quite a few wives. Belle is given an unwanted suitor instead of the two jealous sisters from the original tale. Cinderella still has her mean stepsisters, though. Ariel is an exception, having [[MassiveNumberedSiblings six older sisters]].
* Curiously, every child who had a prominent appearance in ''WesternAnimation/DannyPhantom'' is shown as being an only child. The only one who isn't is Danny himself. He has an older sister and if you wanna stretch it, an OppositeSexClone whom he treats like [[BigBrotherInstinct a little sister]].
-->'''Sam:''' If you don't mind, we'll be over there doing the "glad-I'm-an-only-child" dance."
* On ''WesternAnimation/EdEddNEddy'', Edd, Rolf, Kevin, Jimmy, Johnny and Nazz are all only children. Only Ed/Sarah, Eddy/his brother and the Kanker Sisters are siblings.
* In ''WesternAnimation/KingOfTheHill'', the three main kids--Bobby, Connie and Joseph--are all raised as only children, as were Hank and Luanne. Hank eventually gets two half-brothers, though (one born in his father's old age, one he just never knew about), while Joseph has at least one half-sister but doesn't realize it.
* Of the six main characters in ''WesternAnimation/{{Recess}}'', three (Gretchen, Gus and Mikey) are only children. TJ and Vince have elder siblings who have appeared in the show, and Spinelli has an older brother in jail.
* In the early days of ''WesternAnimation/TheFairlyOddparents'', the only ones shown to be siblings were [[EvilRedhead Vicky]] and [[{{Meganekko}} Tootie]]. Since then, a character is an only child unless a story involving siblings is written. Several seasons later [[AmbiguouslyGay Sanjay]] was revealed to have a step brother that hasn't been mentioned since, and Timmy wished for an older brother [[StatusQuoIsGod that he inevitably unwished]]. In season six Timmy got a godbrother in [[CousinOliver Poof]]. Up in Fairy World, Wanda was eventually revealed to have a sister, and in a currently unaired-in-America episode, Cosmo has a brother.
* Partially averted on ''WesternAnimation/SouthPark'': while most of the minor characters seem to be only children (except for Craig, who has a younger sister), out of the five "main boys" three have siblings, though Butters and Cartman grew up as only children.
** Uh, it seems [[spoiler:Cartman]] can now be crossed off that list of only children. And [[spoiler:Scott Tenorman]]...
* Aside from the WesternAnimation/{{Simpsons}} family, The Flanders', Apu and Manjula, the Hibberts and Sherrie and Terri's family the rest of the couples have one child only. With the exception of the above, most of the kids from the elementary school are only child.
** This is justified in an issue of ''Simpsons Comics'' that ends with all the adults in Springfield becoming sterile.
* Apparently [[AvertedTrope averted]] on ''TotalDrama''--of the twenty-two original contestants, half are stated to have at least one sibling either in dialogue or [[AllThereInTheManual online material]], while only [[DoggedNiceGuy Cody]] and [[{{Geek}} Beth]] are explicitly only children. Bonus points to [[InsufferableGenius Noah]] for being [[MassiveNumberedSiblings the youngest of nine]].
** The fourth season contestants fit this more closely; [[TheChick Zoey]] is the only one specifically stated to be an only child, but the only one who mentions a sibling is [[FarmBoy Scott]], who has a sister.
* In ''WesternAnimation/{{Metalocalypse}}'', Pickles is the only member of Dethklok with a sibling.
* ''WesternAnimation/PhineasAndFerb'' seem to play this halfway--there's the title characters and their sister [[UnknownRival Candace]], [[SingleWomanSeeksGoodMan Jeremy]] / [[EnfantTerrible Susie]] and [[LoonyFan Irving]] / [[AloofBigBrother Albert]] as siblings, but [[TheChick Isabella]], [[BollywoodNerd Baljeet]], [[JerkWithAHeartOfGold Buford]], [[AsianAirhead Stacy]] and [[MadScientistsBeautifulDaughter Vanessa]] all get lots of screen time and give no indication of having a sibling. Adults having siblings seems to be more common--Lawrence has at least one (Ferb has [[MassiveNumberedSiblings six cousins]] from what we know to be Lawrence's brother, and Scottish cousin whose relationship to Lawrence has not been revealed), Linda has Tiana and [[MadScientist Doofenshmirtz]] has Roger.
** Technically Ferb would be an only child in a [[HappilyAdopted strictly biological sense]].
** WordOfGod has apparently confirmed that Stacy and Ginger (the Fireside Girl) are siblings, as are [[GranolaGirl Jenny]] and [[DemotedToExtra Django]].
* On ''WesternAnimation/HeyArnold'', [[BlackBestFriend Gerald]] has [[AloofBigBrother two]] [[AnnoyingYoungerSibling siblings]] and [[JerkassWoobie Helga]] has [[ParodySue a sister]], but otherwise all the kids seem to be only children.
* Most of the babies in ''WesternAnimation/{{Rugrats}}'' were only children, but this changed after the respective releases of the first two movies: [[TheDeterminator Tommy]] gained [[TheVoiceless Dil]] as a younger brother after the first movie, and Chuckie gained Kimi as a stepsister after ''Rugrats In Paris.'' Among the main babies, Angelica is the last only child remaining (Phil and Lil are twins, and Susie is the youngest of four siblings).
** Angelica's being an Only Child was actually made the plot of one episode, where she became ''upset'' at being the only one like this (an unusual turnabout, since in previous episodes she was ''glad'' to have no siblings). The resolution came when Tommy pointed out that [[CrowningMomentOfHeartwarming with the way she occasionally picks on them but still cares, Angelica's really like a big sister to all of the younger kids]].
* In ''{{Mucha Lucha}}'' Rikochet, Buena Girl and the other characters have no brothers or sisters. Only The Flea has a baby sister named [[TheVoiceless Pulgita]].
* On ''TheAdventuresOfJimmyNeutron'', not a single one of the main characters (Jimmy, Cindy, Carl, Sheen or Libby) has a sibling. Jimmy's lack of a brother was even the impetus of the plot of the episode "I, Brobot".
* ''WesternAnimation/NedsNewt'': There is no mention of any of the kids having siblings.
* On ''Codename:KidsNextDoor'' out of Sector V, Numbuh 1 is the only operative to not have any siblings. Numbuh 5 has her older sister [[TeensAreMonsters Cree]] and mentioned having an older brother in passing, Numbuh Four has a baby brother named [[MeaningfulName Joey]], Numbuh 3 has her younger sister [[EnfanteTerrible Mushi]], and Numbuh 2 has his younger brother [[AnnoyingYoungerSibling Tommy]].
* Of the main eight kids on ''TheMagicSchoolBus'', five are only children (Ralphie, Tim, Arnold, Phoebe, and Keesha). Dorothy Ann has a younger sister (Evan), and Wanda and Carlos have younger brothers (William and Mikey).
* Averted for the most part in ''WesternAnimation/MyLittlePonyFriendshipIsMagic''; four of the Mane 6 have one or more siblings, who do have an impact on the plot and even a few [[ADayInTheLimelight episodes]] of their own.
* Laney Penn from ''WesternAnimation/{{Grojband}}'' is the only member to be an only child.
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