History Main / OnlyChildSyndrome

** Abed mentioned that Britta having a brother who works with disabled kids in the pilot, and I'm almost certain Troy mentioned having siblings.

* Ron Weasley asides, almost every other major character in ''Film/HarryPotter'', including the title character and protagonist himself, are only children. However, this averted in the ''Film/FantasticBeasts '' series where pretty much everyone has sibling(s), including protagonist Newt. The only main character who doesn't have a sibling (or rather isn’t confirmed either way) is the BigBad Grindelwald, although Credence’s (who had adopted siblings) supposed biological family ties are questionable. [[note]] Grindelwald tells him his “real name” and claims his “brother” [[spoiler:Dumbledore]] is trying to kill him but something doesn’t add up and Grindelwald is a known liar. If he is who he claims, which again is highly questionable, he’d have three biological siblings. [[/note]]

** Peter Parker (Comicbook/SpiderMan) is an only child. In this case, his parents died a short while after he was born, so they didn't even have the chance to have another kid.

*** Clark Kent/Kal-El is the only child of his biological parents Jor-El and Lara as well as the only child of his adoptive parents Jonathan and Martha. {{Justified}} since Jor-El and Lara might have had more children if they weren't [[EarthShatteringKaboom dead]] shortly after his birth (and usually do, in alternate universes where they survived), and the Kents were unable to have kids through biological means.

** Averted by the 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.

* Except for WesternAnimation/{{Cinderella}} (who has two stepsisters), [[WesternAnimation/TheLittleMermaid Ariel]] (who's the youngest of seven daughters) and [[WesternAnimation/{{Brave}} Merida]] (who's the oldest and only daughter of four kids), all the Franchise/{{Disney Princess}}es are only children -- although you could consider Cinderella an only child in a strictly biological sense since she's the only child that her father had through his first wife. For Rapunzel, her status as an only child is [[JustifiedTrope justified]] in that her biological mother's pregnancy almost killed them both (and it also could've rendered the Queen unable to have more children through biological means).
** In the original poem, ''The Ballad of Hua Mulan'', Mulan had two sisters and a younger brother ([[MythologyGag which is who they named the dog after in the movie]]), who wasn't old enough to enlist in the military when Mulan left (but old enough to kill pigs by the time she came home).

** In the [[Literature/BeautyAndTheBeast fairy tale]] that ''WesternAnimation/BeautyAndTheBeast'' is based on, Belle had two older sisters who were very similar to Cinderella's stepsisters--and in early drafts of the movie, Belle was originally going to have a younger sister named Clarice.
** Just like with Belle in WesternAnimation/BeautyAndTheBeast, early drafts of ''WesternAnimation/{{Moana}}'' were originally going to give the TitleCharacter siblings--in Moana's case, she would've been the youngest and only daughter in a family with several sons and the movie's plot would've had a stronger "girls can do anything" theme. This was dropped in the favor of focusing on a "follow your heart" message, with Moana as an only child who's expected to become the chieftess of her tribe.

* It's glaringly noticeable in ''Franchise/TheLionKing'' that lion cubs are born as individuals when in real life litters are the norm. Even Timon, a meerkat, is presented as an only child in ''WesternAnimation/TheLionKingOneAndAHalf''. [[WesternAnimation/TheLionKingIISimbasPride Kiara]] was [[WhatCouldHaveBeen originally]] written as being a pair of twins but they scrapped the brother in development. Over a decade later she finally got a younger sibling in Kion from ''WesternAnimation/TheLionGuard'' though. [[WesternAnimation/TheLionKing1994 Nala]] was also supposed to have a brother named Mheetu, but he was likewise cut. On the other hand, Mufasa and Scar are brothers so avert this.

* Miaka and almost all the Suzaku Seven in ''Manga/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.

** Just to put in perspective how prevalent this is: the second ''[=StrikerS=]'' Sound Stage has a scene were two minor characters are talking about their families. Both of them mention having multiple siblings, none of who are ever seen or even mentioned outside of this one conversation.

* Every mermaid in ''Manga/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 twins 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.
* 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.

* In ''Manga/OnePiece'', the only major characters with biological siblings are Boa Hancock (two younger sisters) and [[spoiler:Sanji (who left behind a whole SiblingTeam when he ran away as a child)]]. Nami and her sister were adopted orphans, Luffy's brother turns out to have been adopted, and the rest of the Straw Hats are known or assumed to be only children. 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/PokemonAdventures'', there is a rotating cast of 21+ main characters, yet only two are confirmed to have a sibling: Green has his older sister Daisy, and she's most likely only there because she exists in the games. Moon has a yet to be a revealed older sister. That said, in ''Pokemon Emerald'' the rival has a younger brother, however Sapphire never got one most likely due to it being odd if [[RememberTheNewGuy a previously unknown sibling popped up]]. Platinum should also have a younger sister, but it's explicitly stated almost immediately that she's an only child. [[spoiler: It is heavily implied that Platinum is Moon's older sister, meaning that Moon must've been born sometime after the events in Sinnoh.]]
** By contrast, the main characters of the ''Anime/{{Pokemon}}'' tend to avert it. Only Ash, Dawn, Iris, Serena, Sophocles and Goh are confirmed or implied to be only children, while the rest have at least one known sibling. [[note]]Misty has Daisy, Violet and Lily, Brock is the eldest of ten, May and Max have one another, and so do Clemont and Bonnie, Cilan is triplets with Cress and Chilli, Lillie has Gladion, Mallow has Abe, Kiawe has Mimo, and Lana has Harper and Sarah. [[/note]]

* One thing ''ComicBook/ArchieComics'' often got criticized for was that despite the attempt at depicting a "typical teenage" group of friends, an unrealistically high proportion of them were only children. Archie, Reggie, Veronica, and even minor characters like Chuck, Nancy, Moose, Midge and Dilton are all only children. Betty is actually the youngest of three children, but only the most hardcore of fans know that; her sister Polly makes single-digit appearances per ''decade'', and her brother Chic is almost never mentioned even when Polly is. For all storytelling purposes, Betty may as well be an only child. And Jughead gained a baby sister fifty ''years'' after his debut, and it's a coin-toss whether most writers remember Jellybean's existence nowadays. The only significant siblings in the ''Archie'' cast are the twins Jason and Cheryl Blossom, who are about as far from role models as you can get.

* Except for WesternAnimation/{{Cinderella}} (who has two stepsisters), [[WesternAnimation/TheLittleMermaid Ariel]] (who's the youngest of seven daughters) and [[WesternAnimation/{{Brave}} Merida]] (who's the oldest and only daughter of four kids), all the Franchise/{{Disney Princess}}es are only children--although you could consider Cinderella an only child in a strictly biological sense, since she's the only child that her father had through his first wife. For Rapunzel, her status as an only child is [[JustifiedTrope justified]] in that her biological mother's pregnancy almost killed them both (and it also could've rendered the Queen unable to have more children through biological means).

** 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 step sibling.
* Ron Weasley asides, almost every othersthe major characters in ''Film/HarryPotter'', including the title character and protagonist himself, are only children. However this averted in the ''Film/FantasticBeasts '' series where pretty much everyone has sibling(s), including protagonist Newt. The only main character who doesn't have a sibling (or rather isn’t confirmed either way) is the BigBad Grindelwald, although Credence’s (who had adopted siblings) supposed biological family ties are questionable. [[note]] Grindelwald tells him his “real name” and claims his “brother” [[spoiler:Dumbledore]] is trying to kill him but something doesn’t add up and Grindelwald is a known liar. If he is who he claims, which again is highly questionable, he’d have three biological siblings. [[/note]]

* From book to the first movie of ''Film/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.

* 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.

* In the original series of ''Literature/{{Goosebumps}}'', sixteen protagonists of the 20 books are only children. The specific books featuring these protagonists are all four of the ''Monster Blood'' books (since all of them feature the same protagonist), both ''The Curse of the Mummy's Tomb'' and ''Return of the Mummy'' (for the same reason as the Monster Blood books), ''Welcome To Camp Nightmare'', ''Piano Lessons Can Be Murder'', ''My Hairiest Adventure'', ''A Shocker On Shock Street'', ''The Haunted Mask II'', ''The Headless Ghost'', ''Attack of the Jack-O-Lanterns'', ''Vampire Breath'', ''Calling All Creeps'', ''Beware, the Snowman'', ''How I Learned To Fly'', ''The Blob That Ate Everyone'', ''The Haunted School'', and ''Werewolf Skin''. Gretchen in ''How To Kill a Monster'' could be considered an only child in a biological standpoint. Subverted in ''I Live In Your Basement'', [[spoiler:in which the protagonist, Marco, actually dreamed he was the only child to his single mother while comatose from his head injury courtesy of a baseball bat during a softball game and that the girl that he dreamed doing the damage, Gwynnie, is revealed to be his younger sister.]]

* Justified in ''Series/The100''. Many characters were born on The Ark, a space station constructed from 12 original stations to shelter the remnants of the human race after a nuclear war. To conserve resources, the Ark has a [[PopulationControl strict one child policy]], so everyone in the main cast is an only child with the exceptions of Bellamy and Octavia Blake, the latter of whom is an illegal second child who was kept hidden for most of her life.*

** The only aversions are Ward and Koenig. Ward mentions two brothers and a sister: the two brothers played important roles in his back-story and both eventually appeared on-screen, though the sister was never mentioned again and may have been retconned out of existence. Koenig, meanwhile, appears to have a suspiciously well-stocked army of identical [[BackupTwin Back-Up Twins]] [[spoiler:and one sister. Turns out they weren't clones or Life Model Decoys after all, just a bunch of brothers who looked a lot alike. TheUnreveal is PlayedForLaughs after several seasons of speculaton.]]

** Almost all the main characters on both shows 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!

* ''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.

** Nearly all companions in both the classic and revived series are only children. The exceptions are Martha (a brother and a sister), Yasmin (a younger 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}}'').

* This is discussed in an interesting way in ''Series/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.

** Adams (who only joins the cast in the final season) also appears to be an only child, or at least doesn't mention any siblings during her run on the show.

* Most of the characters on ''Series/{{Lost}}'' are only children (or raised as only children) with the exception of Charlie (who has a brother), Hurley (who has a brother), Juliet (who has a sister) and Mr. Eko (who has a brother). Desmond has three unnamed brothers who are never seen, and Charlotte has two unnamed sisters. Boone and Shannon are step-siblings. [[spoiler:Jack and Claire are half-siblings but neither are aware of this.]]
* ''Series/{{Merlin|2008}}'' 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.

** However, this ''does'' still mean that five out of the six friends were the only children in their original family units, which is pretty rare by real life standards.

* Almost all of the core characters on ''Series/TeenWolf'' are only children. Scott, Stiles, Allison, Lydia, Kira, Jackson, Malia and Liam are all only children. Derek and Isaac have siblings, but Isaac's brother is dead, and Derek's two sisters were either murdered or PutOnABus to South America. If Derek had any other siblings, they likely died in the fire along with the rest of his family before the series began.

** Actually, Kelso is mentioned to have 7 brothers and sisters, Fez mentioned at least one sister and Hyde eventually gained a half sister (Angie) through the discovery of his biological father, William Barnett. Technically, this would make Jackie the only only-child.
* 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)

** 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.

** {{Averted}} with many of the minor characters at Blackwell Academy, however. Kate Marsh has two sisters, which can become a minor plot point. Drew and Mikey North are brothers who share a roughly equal amount of screen time. Then there's an interesting case with Nathan Prescott, who has an off-screen older sister who emails him during the game and seems to be a rare positive influence in his life, but who never becomes plot relevant.

** While Jude and Wyatt are never confirmed to have any siblings, they're also never confirmed to be only children like Caitlin is--Wyatt's mentioned to come from a large family, but whether this means a large ''immediate'' family or a large ''extended'' family is uncertain. It seems likely that Jude's an only child, because while he's mentioned his parents quite a few time, he's never mentioned any potential siblings.
** Nikki's a strange example, because a couple episodes in the first season pretty much explicitly state that Nikki has siblings (in "Dude of the Living Dead," Jen claims that Nikki has a sister and in "The Fake Date," Nikki mentions having a nephew). However, later episodes (such as the SeriesFinale) imply that Nikki's an only child like Caitlin is.

* ''WesternAnimation/TheAmazingWorldOfGumball'': The main character's family has three children, but of his approximately twenty classmates, only Penny, Tobias[[note]]His sister, Rachel, [[ChuckCunninghamSyndrome ceased appearing]] even in scenes of his family after season one.[[/note]], and Idaho are known to have any siblings while many of the rest are shown to be only children. Colin and Felix are very similar but not confirmed to be brothers. Among the rest of the school and Elmore's [[LoadsAndLoadsOfCharacters many citizens]], the only ones with known siblings are Margaret, Louie, Hot Dog Guy, and a few very minor characters, while Richard, Nicole and Rocky are only children.
* ''WesternAnimation/{{Arthur}}'': Most of Arthur's friends are only children, with only a handful having at least one sibling. In the earliest seasons, it seemed like Arthur, Francine and Prunella were the only ones who had siblings. Later ones would introduce siblings for Muffy, Binky, Molly and Rattles, and also introduce more characters who have siblings from the get-go, but that's still only a fraction of the cast.

* On ''WesternAnimation/EdEddNEddy'', Ed and Sarah are brother and sister, Eddy has an older brother, and the Kankers' are sisters. Double D, Rolf, Kevin, Jimmy, Johnny and Nazz are all presumably only children--Double D's the only one confirmed to be an only child, while none of the other characters mention having siblings.
* 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 twin sister, and Cosmo has an older brother.

* ''WesternAnimation/{{Hilda}}'': None of the protagonists (Hilda, Frida and David) have 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 or discovers two half-brothers, though (one [[PracticallyDifferentGenerations born in his father's old age]] and one he just never knew about); Joseph also has at least one half-sister through John Redcorn, but [[ObliviousAdoption still doesn't realize that he's related to either of them]].

** Dorothy Ann ("DA" for short) has a younger sister named [[GenderBlenderName Ev]][[TomboyishName an]] while Wanda and Carlos both have younger brothers--Wanda's brother is named William and Carlos's brother is named Mikey.
** While Ralphie, Tim, Arnold, Phoebe and Keesha are never explicitly stated to be only children, whenever their families were shown, we only ever see their parents and no siblings of any kind.

* In ''WesternAnimation/PhineasAndFerb,'' the title characters' three main friends ([[TheBigGuy Buford]], [[BollywoodNerd Baljeet]] and [[TheChick Isabella]]) are all only children, as is [[MadScientistsBeautifulDaughter Vanessa]]. [[AsianAirhead Stacy]] and [[ScoutOut Ginger]] are [[ConnectedAllAlong revealed to be sisters]] once, but otherwise it doesn't come up, while WordOfGod say that [[OutOfFocus Jenny and Django]] are siblings. Interestingly, all of the major adult characters (Linda, Lawrence and Doofenshmirtz]] have siblings. [[AnimalSuperhero Perry]]'s status is unknown.

* 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. Spinelli mentions having an older brother in jail but considering how she actually lied about her parents to makes them seems cooler, it might also be made-up.

* ''WesternAnimation/SheRaAndThePrincessesOfPower'': Castaspella is the sister of Glimmer's father Micah, Bow has [[MassiveNumberedSiblings one dozen]] [[TheGhost unseen]] older siblings, and [[spoiler:Horde Prime and his [[CloneArmy many clones]] (including Hordak)]] refer to each as [[ArtificialFamilyMember "brothers"]]. Siblings are not otherwise mentioned, though Adora, Catra, and several others characters from the Horde are orphans who wouldn't know if they had biological siblings.
* ''WesternAnimation/TheSimpsons'': Aside from the 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.

* From 1979-2016, UsefulNotes/{{China}}'s one child policy prevented urban married couples from having more than one child[[note]]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.[[/note]]. 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 law was slowly walked back over time, first couples where both spouses were only children could have two, then if one spouse was , and now all couples can have two children.
** It's also led to a fairly significant gender disparity; sons have always been more desirable than daughters, and all the more so when a couple is only allowed one child, so many parents aborted female fetuses or gave daughters up to orphanages to be put up for adoption so they could have a boy. At the moment, there are [[https://www.nytimes.com/2017/02/14/world/asia/china-men-marriage-gender-gap.html 33.59]] ''million'' more men than women in China, with the result that a whole lot of men in a family-oriented culture are unable to marry. This was part of the reason China expanded the limit to two children starting in 2016, and is reportedly even considering ending family restrictions altogether.

* Most of the characters in ''WesternAnimation/StarVsTheForcesOfEvil'' don't appear to have any siblings, including Star herself (which is strange considering how many extended family members she has). Ludo and Pony Head both have MassiveNumberedSiblings, and in season 3, [[spoiler:Marco discovers that his parents are going to have another baby--they initially assumed the baby was going to be a boy, but the baby ended up being a girl, who Marco's parents named "Mariposa"]].
** This is actually a plot point in the third season regarding [[spoiler: Eclipsa's daughter, Meteora, who is half monster]]. She was an only child, leading to the reveal that [[spoiler: after Eclipsa was imprisoned, her daughter was replaced with an average girl to become the next queen]].

* In ''WesternAnimation/TeenTitans'', with the exception of Starfire (who has [[CainAndAbel an older sister]] and, [[ComicBook/TeenTitansGo in the tie-in comic]], a younger brother), all of the main Titans are only children. (The comics would eventually state that Raven has many half-siblings through her demonic father, but that became canon after the show ended.)

* Riley in ''WesternAnimation/InsideOut'' is an only child, despite her parents seeming like the type of people who would want a larger family.

* In ''Literature/BridgeToTerabithia'', Leslie Burke is an only child, in contrast to Jess Aarons which have four sisters. This is probably the reason why she's such a ManicPixieDreamGirl, and [[spoiler: also made her fate in the end of the story even more [[TearJerker tear-jerking]].]]..

* ''Literature/TheWheelOfTime'' contains a particularly JustForFun/{{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.]]

* Very much averted in ''Series/TheBigBangTheory''. Howard grew up an only child, but discovered a [[LongLostRelative half-brother Josh]] via his father. Sheldon has an older brother, George, and a twin sister, Missy; Leonard has an unnamed older sister and a younger brother, Michael; Penny has a brother Randall and a sister Lisa; and Raj has a younger sister, Priya, three unnamed brothers, and another unnamed sister; Bernadette has five brothers and sisters (but the number of boys and girls is unspecified); Stuart has a brother and sister; Former main cast member Leslie Winkle has a sister; But this appears not to be the case with Amy and former main cast member Emily Sweeney, they appear to be only children since there was no mention of them having siblings. Numerous aunts, uncles, cousins, nieces, nephews, and grandparents are also mentioned throughout the series.

* Link and Zelda from ''Franchise/TheLegendOfZelda'' have been portrayed as only children in almost all of their [[EternalHero various incarnations]]. The exceptions are ''VideoGame/ZeldaIITheAdventureOfLink'', where the sleeping Zelda had a cruel brother whose evil wizard adviser was responsible for putting her into her slumber, and ''VideoGame/TheLegendOfZeldaTheWindWaker'', where Link's younger sister Aryll gets kidnapped by the Helmaroc King and must be rescued by her brother.

* ''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]].

* ''WesternAnimation/{{Rugrats}}'':
** The only kids to have siblings from the get-go are Phil and Lil DeVille (who're fraternal twins) and Susie Carmichael, who's the youngest of four kids (she has two older brothers and an older sister).
** Tommy and Chuckie both started off as only children, but Tommy gained a younger brother (named Dylan "Dil" Prescott Pickles) after the first movie while Chuckie gained a stepsister named Kimi (as well as a stepmother named Kira) after the second movie.
** Angelica, Tommy and Dil's cousin, is the only kid-character to remain an only child. In most episodes where her status as an only child was a plot point, she typically expressed happiness at having no siblings--however, there have been some episodes where Angelica expresses a desire to have a sibling (particularly a sister), and in one episode from later in the series (after Kimi's added to the cast), Angelica actually expresses sadness about being an only child.

* Ron Weasley asides, almost every othersthe major characters in ''Film/HarryPotter'', including the title character and protagonist himself, are only children. However this averted in the ''Film/FantasticBeasts '' series where pretty much everyone has sibling(s), including protagonist Newt. The only main character who doesn't have a sibling [[note]] or rather aren't confirmed either way [[/note]] is the BigBad Grindelwald. A deleted scene in the first film says that Jacob had an unnamed brother who died in the First World War.

* In the ''[[Franchise/ShinMegamiTenseiPersona Persona]]'' series, this is fairly common. Virtually all party members and most Social Links are only children, and among the few that have siblings, those siblings are usually dead or much older/younger than them.

** Most Pretty Cures are only children. The only Cures who have siblings are the five mentioned above, [[spoiler:[[Anime/FutariWaPrettyCure Hikari]]]], [[Anime/FutariWaPrettyCureSplashStar Mai]], [[Anime/YesPrettyCure5 Rin, Komachi]], [[Anime/FreshPrettyCure Miki]], [[spoiler:[[Anime/HeartcatchPrettyCure the whole Heartcatch Team]]]], [[Anime/SuitePrettyCure Kanade]], [[Anime/SmilePrettyCure Akane, Nao, Reika]], [[Anime/DokiDokiPrecure Alice]], [[spoiler:[[Anime/DokiDokiPrettyCure Aguri]]]], [[Anime/HappinessChargePrettyCure Yuko, Iona]], [[Anime/GoPrincessPrettyCure Towa, Minami]], [[Anime/HugttoPrettyCure Emiru]], [[Anime/StarTwinklePrettyCure Lala, Elena]], and [[Anime/HealinGoodPrettyCure Hinata]].
** This means the remaining Cures who don't have siblings are (besides the mentioned lead Cures) [[spoiler:[[Anime/FutariWaPrettyCure Honoka]]]], [[Anime/YesPrettyCure5 Urara, Karen, Kurumi]], [[Anime/FreshPrettyCure Inori]], [[spoiler:[[Anime/HeartcatchPrettyCure nobody of the Heartcatch Team]]]], [[Anime/SuitePrettyCure Ellen, Ako]], [[Anime/SmilePrettyCure Yayoi]], [[Anime/DokiDokiPrecure Rikka, Makoto]], [[Anime/StarTwinklePrettyCure Madoka, Yuni]], [[Anime/GoPrincessPrettyCure Kirara]], [[Anime/HealinGoodPrettyCure Chiyu]], [[Anime/HugttoPrettyCure Saaya, Ruru, Homare]], and [[Anime/HappinessChargePrettyCure Hime]]. [[Anime/YesPrettyCure5 Urara]] and [[Anime/SmilePrettyCure Yayoi]] are {{Justified| Trope}} due to having a dead [[MissingMom mother]] and [[DisappearedDad father]] respectively before their parents could conceive a second child. [[Anime/HugttoPrettyCure Ruru]] is justified since she's a robot.

* Justified in ''Series/The100''. Most of the characters were born on The Ark, a space station constructed from 12 original stations to shelter the remnants of the human race after a nuclear war. To conserve resources, the Ark has a [[PopulationControl strict one child policy]], so everyone in the main cast is an only child with the exceptions of Bellamy and Octavia Blake, the latter of whom is an illegal second child who was kept hidden for most of her life.

** This means the remaining Cures who don't have siblings are (besides the mentioned lead Cures) [[spoiler:[[Anime/FutariWaPrettyCure Honoka]]]], [[Anime/YesPrettyCure5 Urara, Karen, Kurumi]], [[Anime/FreshPrettyCure Inori]], [[spoiler:[[Anime/HeartcatchPrettyCure nobody of the Heartcatch Team]]]], [[Anime/SuitePrettyCure Ellen, Ako]], [[Anime/SmilePrettyCure Yayoi]], [[Anime/DokiDokiPrecure Rikka, Makoto]], [[Anime/StarTwinklePrettyCure Madoka, Yuni]], [[Anime/HealinGoodPrettyCure Chiyu]], [[Anime/HugttoPrettyCure Saaya, Ruru, Homare]], and [[Anime/HappinessChargePrettyCure Hime]]. [[Anime/YesPrettyCure5 Urara]] and [[Anime/SmilePrettyCure Yayoi]] are {{Justified| Trope}} due to having a dead [[MissingMom mother]] and [[DisappearedDad father]] respectively before their parents could conceive a second child.

** It's also led to a fairly significant gender disparity; sons have always been more desirable than daughters, and all the more so when a couple is only allowed one child. At the moment, there are [[https://www.nytimes.com/2017/02/14/world/asia/china-men-marriage-gender-gap.html 33.59]] ''million'' more men than women in China, with the result that a whole lot of men in a family-oriented culture are unable to marry. This was part of the reason China expanded the limit to two children starting in 2016, and is reportedly even considering ending family restrictions altogether.

* ''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.

** Also, we later learn that Thirteen ''does'' have a sister and a brother, the latter of whom is [[spoiler: euthanized by Thirteen when his Huntington's Disease worsens, resulting in Thirteen being imprisoned for half a year]].

** Harry Potter's parents died when he was fifteen months old. At one point, Harry wonders what his life would have been like if his parents had lived, and imagines that he might have had younger siblings. He did live with his cousin Dudley, also an only child, but they do not have a sibling-like relationship. (And Dudley is probably an only child because Vernon and Petunia think having more than one child is unseemly.)

* Averted in ''Manga/KaguyaSamaLoveIsWar''. All but one of the student council members (Miko) have at least one sibling. This even extends to the supporting cast, where only Osarai and Hayasaka are confirmed to be only children. And even those three are justified since Miko and Hayasaka's parents constantly being busy with work ties into their backstories, while Osaragi's father is dead according to the official fanbook.

** In the original poem, ''The Ballad of Hua Mulan'', Mulan had two sisters (one older and one younger) and a younger brother ([[MythologyGag which is who they named the dog after in the movie]]), who wasn't old enough to enlist in the military when Mulan left (but old enough to kill pigs by the time she came home).

** Another curious case is that of Libby. In "Make Room for Daddy-O", a young boy acts as the legs to Libby's "cutting-person-in-half" magic trick and runs after Libby and her dad after the trick is completed. It can be inferred that the boy is her brother, but he never appears after that episode nor is it directly ever stated that the boy is Libby's brother (in fact, she never mentions any siblings during the show).

* ''WesternAnimation/DannyPhantom:'' Danny and Jazz are siblings, and if you wanna stretch it, he treats [[OppositeSexClone Dani]] like [[BigBrotherInstinct a little sister]]. However, ''every other secondary character''--[[LoveInterest Sam]], [[ExtrovertedNerd Tucker]], [[DatingCatwoman Valerie]], [[JerkJock Flash]], [[AlphaBitch Paulina]], etc.--seems to be an only child.

* While most of the main characters in both ''[[Franchise/AvatarTheLastAirbender Avatar]]'' series have siblings, we've never known of an actual Avatar that did: [[WesternAnimation/AvatarTheLastAirbender Aang]] and all previous Air Nomad Avatar (like Yangchen) come from a society with NoBloodTies. [[WesternAnimation/TheLegendOfKorra Korra]], Roku (the Avatar before Aang), Kyoshi (Roku's predecessor), and Wan (the first Avatar) are all only children. The most recent Avatar who hasn't been confirmed either way is Kyoshi's predecessor, Kuruk.

** Also, we later learn that Thirteen ''does'' have a sister and a brother, who is [[spoiler: euthanized by Thirteen when his Huntington's Disease worsens, and this results in Thirteen being imprisoned for a year]].
* ''Series/HowIMetYourMother'': Out from the five main characters, Lily is the only one who does not have siblings considering that [[DisappearedDad her dad didn't do his parental responsibilities very well]]. Ted has a younger sister who very one appears once in the show]]. Robin also has a younger sister. Marshall has three older brothers [[BigBrotherBully who are more or less jerks to him]]. And Barney has a black older half-brother from his mother's side and three half-siblings from his biological father's side.

* 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 mentions having an older brother in jail.

** Most Pretty Cures are only children. The only Cures who have siblings are the five mentioned above, [[spoiler:[[Anime/FutariWaPrettyCure Hikari]]]], [[Anime/FutariWaPrettyCureSplashStar Mai]], [[Anime/YesPrettyCure5 Rin, Komachi]], [[Anime/FreshPrettyCure Miki]], [[spoiler:[[Anime/HeartcatchPrettyCure the whole Heartcatch Team]]]], [[Anime/SuitePrettyCure Kanade]], [[Anime/SmilePrettyCure Akane, Nao, Reika]], [[Anime/DokiDokiPrecure Alice]], [[spoiler:[[Anime/DokiDokiPrettyCure Aguri]]]], [[Anime/HappinessChargePrettyCure Yuko, Iona]], [[Anime/GoPrincessPrettyCure Towa, Minami]], [[Anime/HugttoPrettyCure Emiru]], [[Anime/StarTwinklePrettyCure Lala, Elena]] and [[Anime/HealinGoodPrettyCure Hinata]].
** This means the remaining Cures who don't have siblings are (besides the mentioned lead Cures) [[spoiler:[[Anime/FutariWaPrettyCure Honoka]]]], [[Anime/YesPrettyCure5 Urara, Karen, Kurumi]], [[Anime/FreshPrettyCure Inori]], [[spoiler:[[Anime/HeartcatchPrettyCure nobody of the Heartcatch Team]]]], [[Anime/SuitePrettyCure Ellen, Ako]], [[Anime/SmilePrettyCure Yayoi]], [[Anime/DokiDokiPrecure Rikka, Makoto]], [[Anime/StarTwinklePrettyCure Madoka, Yuni]],[[Anime/HealinGoodPrettyCure Chiyu]], [[Anime/HugttoPrettyCure Saaya, Ruru, Homare]], and [[Anime/HappinessChargePrettyCure Hime]]. [[Anime/YesPrettyCure5 Urara]] and [[Anime/SmilePrettyCure Yayoi]] are {{Justified| Trope}} due to having a dead [[MissingMom mother]] and [[DisappearedDad father]] respectively before their parents could conceive a second child.

* Most lead Pretty Cures from the [[Anime/PrettyCure franchise]] are only children, with the exception of [[Anime/FutariWaPrettyCure Nagisa]] and [[Anime/FutariWaPrettyCureSplashStar Saki]]. However, [[spoiler:[[Anime/HeartcatchPrettyCure Tsubomi]] gets a newborn sister in the final episode]] and [[Anime/FreshPrettyCure Love and Setsuna]] become adopted sisters after the first half of the season. [[Anime/SuitePrettyCure Hibiki]] is actually the only lead Cure who suffers from being an only child while [[Anime/SmilePrettyCure Miyuki]], [[Anime/DokiDokiPrecure Mana]] and [[Anime/HappinessChargePrettyCure Megumi]] don't seem to care.
** Most Pretty Cures are only children. The only Cures who have siblings are the five mentioned above, [[spoiler:[[Anime/FutariWaPrettyCure Hikari]]]], [[Anime/FutariWaPrettyCureSplashStar Mai]], [[Anime/YesPrettyCure5 Rin, Komachi]], [[Anime/FreshPrettyCure Miki]], [[spoiler:[[Anime/HeartcatchPrettyCure the whole Heartcatch Team]]]], [[Anime/SuitePrettyCure Kanade]], [[Anime/SmilePrettyCure Akane, Nao, Reika]], [[Anime/DokiDokiPrecure Alice]], [[spoiler:[[Anime/DokiDokiPrettyCure Aguri]]]], [[Anime/HappinessChargePrettyCure Yuko and Iona]].
** This means the remaining Cures who don't have siblings are (besides the mentioned lead Cures) [[spoiler:[[Anime/FutariWaPrettyCure Honoka]]]], [[Anime/YesPrettyCure5 Urara, Karen, Kurumi]], [[Anime/FreshPrettyCure Inori]], [[spoiler:[[Anime/HeartcatchPrettyCure nobody of the Heartcatch Team]]]], [[Anime/SuitePrettyCure Ellen, Ako]], [[Anime/SmilePrettyCure Yayoi]], [[Anime/DokiDokiPrecure Rikka, Makoto]], and [[Anime/HappinessChargePrettyCure Hime]]. [[Anime/YesPrettyCure5 Urara]] and [[Anime/SmilePrettyCure Yayoi]] are {{Justified| Trope}} due to having a dead [[MissingMom mother]] and [[DisappearedDad father]] respectively before their parents could conceive a second child.

** Franchise/WonderWoman:
*** Before the New 52, Diana's creation out of clay was a once-in-an-eternity event, and Hippolyta was lucky to have even one child (and many Amazons were jealous of her for it) without getting into the whole issue of [[http://en.wikipedia.org/wiki/Nubia_(comics) Nubia's]] place in canon. After the New 52, Diana is yet another child of Zeus, and she has a lot of half-siblings as well as a twin brother named Jason.
*** [[ComicBook/WonderGirl Donna Troy]] was the child of a teen mother who died young and spent a significant part of her childhood in foster care before she was rescued by Diana and adopted by Hippolyta as Diana's younger sister. Or at least she was before the ContinuitySnarl happened.