->''"She never realized the irony of calling me a son of a bitch."''
-->-- '''Creator/JackNicholson''' (about his mother)

Many family secrets are kept both in RealLife and fictionland. Orphans are one of the most popular character tropes, especially ones who turn out not to be orphans; the most famous example of this is the LukeIAmYourFather situation wherein a thought-to-be unrelated character (often a villain, usually the BigBad or TheDragon) turns out to be TheHero's parent. But sometimes these parents are hidden closer to home; sometimes, for some reason or other, they pose as a different relative -- aunt, uncle, etc. and play a part in bringing up the child.

The most typical example of the trope would be an "older sister" who is actually a mother and "parents" who are really grandparents, a situation that was frequently TruthInTelevision before premarital sex and childrearing out-of-wedlock became less taboo. (See the RealLife section for more historical detail.) In fiction set in the past, this may still be the reason for the Switcheroo. In contemporary society, the damage done by forcing the family to lie to the child and to the outside world is generally seen as much worse than an admitted out-of-wedlock birth -- even if the child is being RaisedByGrandparents or [[{{Nephewism}} other relatives]], they will know who their birth mother is. Contemporary Switcheroos (both in real life and in fiction) are likely to be concealing a much darker and more potentially damaging family secret, such as a pregnancy caused by rape or incest.

What effect this has on the child varies from story to story, and how TheReveal happens. It should be pointed out that sometimes the focus of the story is the "older sister" and not the child, or the focus is on both equally.

See also: LukeIAmYourFather, LukeYouAreMyFather, and StigmaticPregnancyEuphemism. Compare CainAndAbelAndSeth.

'''Note that any Switcheroo is a straight use of this trope. It does not have to involve a parent in any way, and there are no inversions or gender-inversions. Also, beware of spoilers.'''



[[folder:Anime & Manga]]
* This trope is very popular in Japanese fiction, since it helps create a "painless" end in BrotherSisterIncest or even ParentalIncest works. For example, in this way LittleSisterHeroine is made at least partially high-grade by LoveInterest in ''LightNovel/SwordArtOnline'' and ''VisualNovel/KanaLittleSister''. However, ''Manga/KoiKaze'' deliberately averted this as an overly used cliche. Also, expect frequent use with DeliberateValuesDissonance in works that criticize abusive attitudes towards women because of patriarchal foundations in modern Japan.
* In ''Manga/AirGear'' [[spoiler:Akito is Kaito's son, not his brother.]]
* In ''Literature/{{Another}}'', [[spoiler:twin sisters Mitsuyo Fujioka and Yukiyo Misaki both became pregnant. Mitsuyo gave birth to twin girls, Mei and Misaki, but Yukiyo miscarried and fell into depression. Meanwhile, the Fujioka family was having financial problems from caring for two children, so when the twins were two, they sent Mei to the Misaki family. They presumably sent Mei because if they sent Misaki, her name would be Misaki Misaki. The switch was kept secret for several years, but their grandmother slipped up one day. The girls began to secretly spend time together, but sadly, Misaki died a few years later.]]
* In ''Anime/DigimonAdventure'', [[spoiler:Izzy/Koushirou Izumi]] overheard his parents talking one night about how they were not his biological parents, and they wanted him to remain [[ObliviousAdoption ignorant of this]] until he was older. After a period of angsting about it he found out that his father was in fact his biological father's cousin, and that they had adopted him after his birth parents had died since they had recently lost a child of their own, and the family reconciles.
* In the second half of ''Manga/{{Bokurano}}'' it turns out that the parents of [[spoiler: Jun are actually his aunt and uncle, and accordingly, his younger sister Kana is actually his cousin. This was necessary because his real father died during gang warfare and the mother entrusted her child to her relatives, since she was also in danger. And although she approaches with her son and becomes a volunteer to save him, unfortunately she dies before he knows the truth.]]
* ''Manga/KoiKaze'' deliberately teases the reader with this, and then specifically averted to show that this is an artificial happy ending and trying to deconstruct the genre, rejecting tropes like this.
* Played for drama and in general Zig Zagged in ''LightNovel/TheIrregularAtMagicHighSchool''. In the 16th volume, [[spoiler: Maya, the aunt of the protagonists Tatsuya and Miyuki Shiba, states that Tatsuya is actually her son, which turns the brother and sister into first cousins ​​and makes it possible for them to get married. However, further in the volume it turns out that this is a lie invented for the purposes of RoyalInbreeding, which becomes possible due to the fact that Miyuki was created artificially as DesignerBaby from the DNA of Tatsuya's parents, which technically makes them "unusual" siblings and will ensure the birth of healthy children in spite of the real BrotherSisterIncest. It is implied that as a result of this, [[AuthorsSavingThrow they are genetically closer to half-siblings anyway]], as Maya went to lie clearly not afraid that the DNA test would show something unusual, and real Tatsuya's mother will be very difficult to identify, since Maya was the twin of their mother and has a similar DNA.]]
* ''Manga/BunnyDrop'' also plays with this. First we are told that Rin is a very young aunt of the protagonist, who was born from his grandfather's connection with a young girl who worked in his house. However, [[spoiler: at the end of the series it turns out that his grandfather just announced Rin as his daughter to hide the fact, that she was the result of an unwanted pregnancy and she prevented her mother from building a career.]]
* In ''The Will'' by Creator/JunjiIto, Hiroko's sister Taeko commits suicide, leaving a note in which she promises to curse someone from beyond the grave -- but the intended victim's name is obscured by a blood stain. It's revealed that Taeko was actually Hiroko's cousin, and her "parents" were her biological aunt and uncle (leading the family to believe that the reason for her suicide was the stress of finding out she was adopted.)

[[folder:Comic Books]]
* In Wildstorm comics' ''ComicBook/WildCATs'' it was recently revealed that Zealot, who has looked out for her 'little sister' Savant since she was born, is actually Savant's mother. (And that Majestic was her father). However the ResetButton was pushed on the entire title the issue after this was revealed, so God only knows if it's still in-continuity.
* Subverted in ''ComicBook/{{Transmetropolitan}}''. Not only is the child entirely unwanted when it shows up--it also has ''no head'', which fails to surprise anyone who knows the alleged father. And then it [[spoiler:turns out to be a walking humanoid bomb]].
* Kelly O'Hare, title character of the 1983 (or so) comic ''ComicBook/CuteyBunny'' has a dependent, Taffy; they both have a youthful enough appearance to have characters remark: 'sister, huh...?'
* In the ''ComicBook/{{Hellblazer}}'' spinoff comic ''Lady Constantine'', [[spoiler: Johanna Constantine travels with her "little brother" Mouse, who's actually a girl posing as a boy. Johanna's reason for the disguise is that "bad things happen to little girls on the streets of London"... foreshadowing the reveal that Mouse is actually Johanna's daughter, and implying that the pregnancy was the result of rape.]]
* ''Comicbook/{{Trouble}},'' [[CanonDiscontinuity theoretically]] a romantic ''ComicBook/SpiderMan'' prequel miniseries, infamously made Aunt May the biological mother of Peter Parker. Richard Parker was still his father; in this version, Mary and May were best friends dating two brothers, but May and Richard had an affair. Mary agreed to pretend May's baby was hers, not even telling Richard the truth, and when they died little Peter was passed back to "Aunt" May and Uncle Ben anyway.
* In some incarnations, [[ComicBook/{{Batgirl}} Barbara Gordon]] is the niece of Jim Gordon that he adopted after her biological parents died.

[[folder:Fan Works]]
* ''Fanfic/ChildOfTheStorm'' has this at the centre of one of its key reveals: [[spoiler: Peggy Carter]] wasn't [[spoiler: Alison Carter's]] older sister. She was her mother. The crucial parts, however, are the identity of the father, [[spoiler: Steve Rogers]] and what this means for [[spoiler: Alison's]] granddaughter, [[spoiler: Carol Danvers.]]
** It's also at the key of another reveal in ''Ghosts of the Past'': [[spoiler: Rachel Grey isn't Jean Grey's daughter, and Maddie Pryor isn't her clone. Instead, they're a CompositeCharacter and Jean's stolen at birth twin-sister.]]
* Has occasionally cropped up in ''Series/{{Glee}}'' fics, after Creator/MattBomer was cast as Cooper, Blaine's ambiguously aged older brother.
* ''Fanfic/TheGodEmpressOfPonykind'': Luna is technically Celestia's daughter, but Celestia insists Luna call her "sister" due to [[GodEmperor Celestia's]] [[Literature/HorusHeresy bad experiences with having sons]].
* ''Fanfic/AlexandraQuick'' has [[spoiler: Alex herself. Her mother, Claudia, is actually her oldest sister, who walked away from the wizard world. Her real mother is Hecate Grimm, who unfortunately suffers from amnesia so severe that her sister, Lilith, turned her into a cat, which has allowed Hecate to live a moderately decent life.]]
* This is brought up in the middle of ''[[Fanfic/LunaTheMatchmaker Curse of the Werepony]]'', where it is explained that [[spoiler:Sweetie Belle]] is [[spoiler:Rarity]]'s biological daughter, and their "parents" are actually cousins of [[spoiler:Rarity]]'s real parents, who disowned her.
* The same setup is shown in ''[[Fanfic/TheDearSweetieBelleContinuity Dear Sweetie Belle]]'', though their "parents" really are [[spoiler:Rarity]]'s parents in this one.
* An entire [[http://www.fimfiction.net/group/204132/applejack-is-apple-blooms-mother group]] on Website/FimfictionDotNet is dedicated to stories where Applejack is revealed as Apple Bloom's biological mother, but passed her off as her sister. At least one of them also has Big Macintosh as Applejack's [[FlirtyStepsiblings stepbrother]] and Apple Bloom's biological father.
** ''[[https://www.fimfiction.net/story/367008/yes-my-lady Yes, My Lady]]'', a crossover with ''Manga/BlackButler'', pulls off both this and RelatedInTheAdaptation by not only having Apple Bloom as Applejack's daughter, but revealing that her father is Filthy Rich and Diamond Tiara is her separated-at-birth twin sister.
* ''WesternAnimation/{{Daria}}'' fanfiction sometimes reveals that Daria is Aunt Amy's daughter, due to their UncannyFamilyResemblance and similarly [[DeadpanSnarker snarky]] personalities.
* Creator/SamAndMickey's ''Franchise/{{Barbie}}'' parodies depict Barbie's "little sisters" as the illegitimate daughters of Barbie and Ken, whom Barbie publicly refers to as her sisters.
* In ''Fanfic/EmpathTheLuckiestSmurf'', Empath was left in the dark until his 150th birthday that he was actually Papa Smurf's only biological son, while Brainy himself grew up thinking that he was Papa Smurf's only biological son. (He turned out to be Empath's half-brother through the same mother.)

[[folder:Films -- Live-Action]]
* ''Film/{{Chinatown}}'', though here [[spoiler:they were both sisters and mother and daughter; the father, Noah Cross had raped his daughter, and she gave birth to a girl.]]
* ''Film/{{Shara}}'': A teenage girl's mother tells her she's actually her aunt.
* In ''Film/CookiesFortune'', Emma (Creator/LivTyler) finds out her mother is not Cora (Creator/JulianneMoore), but her "aunt" Camille (Glenn Close).
* In ''Film/TromeoAndJuliet'', the title characters find out they are, in fact, brother and sister. [[IncestIsRelative They decide to continue their romantic relationship anyway.]] It is a ''Creator/{{Troma}}'' movie, after all.
* In ''Film/DiggingToChina'', the protagonist learns that [[spoiler: her sister is really her mother after her grandmother (who she thought was her mother) dies.]]
* In the book and film versions of ''Film/DevilInABlueDress'', White Daphne and Black Frank are assumed to be lovers when they are spotted meeting in secret. In reality [[spoiler: they are half-siblings, sharing the same mother but with different fathers.]]
* In ''Film/JumpingTheBroom'', Sabrina, the protagonist, [[spoiler: learns that her Aunt Geneva is actually her mother, having become pregnant as a teen and abandoned by a man who turned out to be married. Sabrina was adopted by Geneva's older sister Claudine and her husband.]]
* In ''Film/RunLolaRun'', during Lola's second run she ends up in a slightly [[{{Understatement}} agitated]] situation with her father and the following conversation takes place.
-->'''Father:''' Besides, I could never have fathered a freak like you.\\
'''Lola:''' Yeah... but you did, you Jerk!\\
'''Father:''' No, I didn't!
* In the 1978 ''Film/SupermanTheMovie'', Martha Kent suggests that she and Jonathan tell people that the baby boy they found was "a child of my cousin's... and just now orphaned."
* In ''Film/JennyJuno'', Jenny's older sister suggests that they hide Jenny until she's had her baby, and then send it to be raised by a relative in America who recently gave birth. The relative can then claim to have had twins. The mother dismisses the idea as too much like a soap opera.
* In ''Film/ImmortalBeloved,'' [[spoiler:[[ArtisticLicenseHistory Beethoven's "nephew" Karl turns out to be his son.]]]]
* Russian comedy ''Shirly-Myrly'' is this trope taken to the extreme. Not only the main character, Krolikov, was raised by his aunt pretending to be his mother, but he also has a number of twin brothers who are also raised by various stepmothers. Also played for AnAesop, since Krolikov is an outspoken anti-semit early in the film, so when his birth father revealed to have been a jew, it strikes him worse than the earlier revalation he's actually a stepchild. Each of his twins also believed himself to be a descendant of some other ethnic group, such as Jews, Romani or African. They all have some racist sentiment against each other, which they have to overcome upon learing they are brothers and actually hail from a very mixed common descent.
* ''Film/{{Soapdish}}'' includes an example as part of its parody of soap opera conventions. Though 1970s ''The Sun Also Sets'' co-stars Celeste Talbert and Jeffrey Anderson's relationship was public knowledge, they were not married when he got her pregnant. To protect her "America's sweetheart" image, she broke up with Jeffrey and had his character killed off, then had her own character written out for a few months while she spent her pregnancy at her parents' house in Iowa. She claimed that her daughter, Lori, was actually the daughter of her twin sister Simone and her husband, who were killed in a car accident when Lori was too young to remember them. But when first Lori and then Jeffrey are added (re-added in the latter case) to the cast of ''The Sun Also Sets'' and not only seem to be developing a romantic interest in each other off camera but are given a kissing scene in the show, Celeste is forced to confess everything to prevent them from committing accidental incest.

* In ''Literature/ABrothersPrice'', the Whistlers suspect that the younger Brindle sisters were actually not fathered by their alleged father, but by Balin Brindle, the son of the family. There's a twelve year gap in births, and the father is described as very frail and feeble. [[spoiler: And then there is Kij Porter's daugther Eldie, whose father, too, is someone other than is officially claimed.]]
* A bizarre example occurs in ''Literature/DragonBones'', where Oreg is actually related to the Hurog family (he's the bastard son of some ancestor, several generations removed). When he needs a cover identity, because [[Really700YearsOld the truth]] [[FriendlyGhost is too strange]], Ward opts for introducing him as a "cousin" which is the usual euphemism for bastard offspring fathered by some male family member. So the people who see through the euphemism know the truth, namely that Oreg is a bastard son ... just not ''whose'' bastard son.
* ''Literature/CodexAlera'' has [[spoiler:Tavi's "aunt", Isana,]] who hides their real relationship from everyone (including her son). She had a damn good reason to do so, though, given that [[spoiler:the boy's father is the presently deceased heir to the realm, meaning that [[SecretLegacy he's now the sole legitimate heir to the throne]]. Since Septimus was assassinated, she felt that the only way to protect Octavian was via obscurity; as part of this she suppressed his growth to make it appear that he was born too late to be Septimus' offspring. Unfortunately, this accidentally suppressed his PersonOfMassDestruction-level ElementalPowers as well, leaving him as [[TheCallPutMeOnHold the only person in the country with absolutely no powers]].]]
* In ''Literature/HisDarkMaterials'', Lyra's [[spoiler:"Uncle" Lord Asriel is actually Lyra's father, her mother is Mrs. Coulter, making Lyra have a case of both this trope and LukeIAmYourFather]]. This masquerade was to cover up an affair.
* The ''Literature/AlexDelaware'' novel ''Blood Test'' by Jonathan Kellerman, has this as the big reveal, with the older sister being the mother of the younger [[spoiler:and then having the same father.]]
* A slightly confusing example occurs in the novel ''Literature/AYellowRaftInBlueWater'': [[spoiler:Christine is really the daughter of Ida's father and her aunt Clara on her mother's side, making her technically Ida's three-quarter sister (or something like that) but Christine was raised to believe she was Ida's in order to cover up the affair that created her. This is made even weirder by Ida's insistence that Christine call her "Aunt Ida."]] In the end only [[spoiler:Ida]] and the reader knows this.
* On a similar line, in ''Travels with my Aunt'', the aunt turned out to the mother, while his 'mother' really was his aunt taking responsibility for her sister's mistake.
* In the third book of ''Literature/TheRubyRedTrilogy'' it is revealed that [[spoiler: Grace, the woman who raised main protagonist Gwyneth, is actually the cousin of Gwyneth's biological mother Lucy. Lucy had to flee from [[BigBad The Count]] only days after giving birth and couldn't take her baby with her. Grace kept it a secret to protect Gwyneth.]]
* In ''A Suitable Boy'' [[spoiler:Saeeda Bai was raped at a young age by the Nawab Sahib of Baitar, resulting in a daughter, Tasneem. To protect the Nawab Sahib's reputation, they pretend Tasneem is Saeeda's sister. This comes back to haunt the Nawab Sahib when his son falls in love with Tasneem.]]
* ''Literature/ASongOfIceAndFire'':
** The Baratheon children Joffrey, Myrcella, and Tommen learn that [[spoiler: their uncle Jaime Lannister is their biological father...[[{{Twincest}} but still also their uncle]]]]. They reject this notion, as their mother vehemently denies it as a scandalous rumor meant to cheat them out of their inheritance.
** Similarly, Prince Aemon the Dragonknight, the uncle of King Daeron II Targaryen "The Good" on both sides (due to Daeron's parents being siblings, as per Targaryen tradition) was actually his father. However, many think it is more likely that King Aegon IV Targaryen "The Unworthy" began the rumors himself out of spite at his only legitimate son, as Aegon wanted to make one of his bastard children his heir.
** There are rumors around the Twins that Lord Walder Frey's seventh wife Annara Farring conceived her children with Black Walder, Lord Walder's great-grandson via his first wife Perra Royce. If that's the case, it means Arwyn, Wendel, Colmar, Waltyr, Elmar and Shirei's great-nephew is actually their father, while their father is actually their great-great-grandfather. Black Walder is also rumored to have had affairs with many of the women round the Twins (such as his both of his brothers' wives), even those who are also [[KissingCousins descended]] from Lord Walder. [[BigScrewedUpFamily As if the Frey family tree wasn't already bizarre and tangled enough]].
** Historically, Corlys Velaryon claimed Addam of Hull and Alyn of Hull as his grandchildren. However Corlys' son Laenor was in the TransparentCloset, so its much more likely that the boys were actually his sons. To make things more complicated, Alyn, who succeeded Corlys, married his [[KissingCousins cousin]] Baela, who if the rumors were true was actually his half-niece.
** It is theorised by many fans that Lord Eddard "Ned" Stark's illegitimate son Jon Snow [[spoiler:is really his nephew, the son of his late sister Lyanna Stark with Rhaegar Targaryen. Ned spends the rest of his life protecting his nephew, passing him off as his own son to keep him safe from their family's enemies and honour ThePromise he made to his dying sister, Lyanna. Claiming Jon as his own illegitimate child, Ned accepts the stain on his honour and permanently sours relations with his new wife to protect Jon -- his nephew and his sister's only child -- from the fatal wrath of Robert Baratheon]].
* This is one of the main plot points in Catherine Forde's ''Fat Boy Swim'' [[spoiler:Jim Kelly's Aunt Pol is his mother, and "Mum" is his grandmother.]]
* A very traditional example: in the first book of the ''Literature/{{Stravaganza}}'' series, [[spoiler:Arianna]] discovers that her "parents" are actually her aunt and uncle, and her mother is really ''[[spoiler:the Duchessa of Belezza]]''.
* In the Creator/MaeveBinchy book ''Evening Class'', a character is stunned to realize that her older sister is actually her mother. Ironically, she is told this by someone who was completely unaware of the secret--she merely saw the two together and assumed. When the girl confronts her "sister" and asks her point blank if she's her mother, the woman's silence is of course, her answer. Despite the Irish/Catholic setting of Binchy's books and the time period the book is set during, it's revealed that this was NOT done out of shame because of the situation--the woman explains that her mother's reaction to her pregnancy was to simply say "won't it be grand to have another baby around here", thus revealing that she had her family's unconditional love and support. The "deception" simply came about because no one ever bothered to explicitly tell the girl what the situation was--indeed, they thought that she already knew.
* In Torey L. Hayden's ''Beautiful Child'', it is revealed that one of a poor mother's large brood is actually the product of her boyfriend and her mentally retarded teen daughter. The child herself is unaware of this. This is a true story.
* When visiting her "older sister" who is comatose in hospital, Kit, the main character of Maureen [=McCarthy's=] ''When You Wake and Find Me Gone,'' receives a letter written by her "sister" which reveals that she is really Kit's mother and that her father is somewhere in Ireland.
* In ''To Hear a Nightingale'' by Charlotte Bingham, Cassie grows up being abused by her grandmother and told what a slut her mother was. When her grandmother dies she finds out [[spoiler:that her "grandmother" was really her mother. The woman had had an affair when in her 40s and hadn't ever accepted having a child.]] This nearly destroys Cassie.
* ''Literature/MaximumRide'': [[spoiler:Jeb Batchelder is Max's biological father as well as her guardian, and Dr. Martinez is her biological mother.]]
* In ''Literature/ShanghaiGirls'', which takes place in the 1920s, [[spoiler:May's daughter is raised by her sister Pearl as her child, since even though May was married, she had never had sex with her husband.]]
* Very common in the works of Creator/VCAndrews:
** In ''Literature/TheWildflowers'' series, [[spoiler:Cat is raised as her sister Geraldine's daughter. She is initially led to believe that she is Geraldine's biological daughter, then her adoptive daughter. It turns out neither is true - Geraldine's mother gave birth to Cat, and they are half-sisters.]]
** In the ''[[Literature/CutlerSeries Cutler]]'' series by the same author, Lillian discovers that her mother Georgia [[spoiler:is actually her aunt - Lillian's birth mother was Georgia's sister who died shortly after Lillian was born.]] Later, when Lillian [[spoiler:is raped and gives birth to Charlotte, the family pretends that Georgia is Charlotte's mother too.]]
** Also in the ''Cutler'' series, protagonist Dawn was abducted as a baby and is returned to her real parents, the wealthy Randolph and Laura Sue Cutler. However, it turns out Randolph isn't her father at all - [[spoiler:Randolph's own father had raped Laura Sue and is Dawn's biological father. Randolph is really her half-brother.]]
** In the ''[[Literature/TheCasteelSeries Casteel]]'' series, Heaven Casteel learns that her supposed step-grandfather is actually her father, thanks to him raping her mother, meaning that she isn't related at all to any of the people that she thought were her siblings. In a later book, her daughter Annie is horrified to find herself developing feelings for her half-brother Luke (the result of her father's drunken one-night with Heaven's "sister" Fanny), only to have it turn out that ''she'' is the result of her mother's own adulterous liaison, meaning she and Luke aren't related at all.
** The ''[[Literature/DollangangerSeries Dollanganger]]'' series reveals that [[spoiler:Chris Sr's mother Alicia was raped by his older half-brother Malcolm, leading to the birth of Corrine. Therefore, while Chris Sr and Corrine married believing themselves to be "only" (half-)uncle and niece, they were in fact ''also'' (half-)brother and sister.]]
** In the ''[[Literature/LoganSeries Logan]]'' series, Melody Logan's mother Haille was raised as the adoptive daughter of Olivia and Samuel Logan, but [[spoiler:her biological mother turns out to be Olivia's sister Belinda.]] This also means that [[spoiler: Melody and Cary are second cousins rather than first cousins, paving the way for them to marry.]]
** In ''Literature/MySweetAudrina'', Vera is revealed to be Audrina's half-sister as well as her cousin, due to Damian Adare having had an affair with Vera's mother.
* Chris Crutcher did this in two of his stories. In ''Deadline'', [[spoiler:Dallas]] is really the mother of her younger brother; this is kept a secret because [[spoiler:he was the result of being raped by her uncle at a young age.]] In ''Ironman,'' [[spoiler:Stacy Ryder's]] younger brother is really her and [[spoiler:Preston's]] son.
* Jayfeather, Lionblaze, and Hollyleaf of the ''Literature/WarriorCats'' series are raised as Squirrelfight's and Brambleclaw's kits. However, [[spoiler: Leafpool, the sister of Squirrelflight and Jayfeather's mentor]] is their real mother. When this is [[TheReveal revealed]] to the three, Hollyleaf doesn't take it well.
* In ''Literature/GreatExpectations'', [[spoiler:Molly]] and [[spoiler:Abel Magwitch]] are revealed to be the parents of [[spoiler:Estella.]]
* In Creator/RafaelSabatini's ''Literature/{{Scaramouche}}'', [[spoiler:Mme. la Comtesse de Plougastel]] to Andre-Louis.
* In ''Literature/IshqAndMushq'', Sarna's illegitimate daughter, Nina, was raised by Sarna's mother as her own daughter.
* In Creator/AmyTan's novel ''The Bonesetter's Daughter'', the protagonist [=LuLing=] is raised by [[spoiler:her biological father's brother and his wife]] and her real parents are [[spoiler:her "babysitter" Precious Auntie, the titular character, and her murdered fiance. This explains why her "younger sister"/cousin [=GaoLing=] is pampered like an eldest daughter.]]
* In the ''Literature/{{Janie}}'' series, the titular character is raised by two people she believes are her parents. As it turns out [[spoiler: ''they'' believe they are actually her grandparents and she is the daughter of their estranged daughter, when in reality, both are incorrect, and she was actually kidnapped from a third, unrelated family.]]
* Marcus [=LaGrone=]'s ''[[Literature/TheHighlandsOfAfon Dawn]]'' the titular character discovers that her "uncle" and adoptive father Lewellyn is actually her biological father, and the actual arrangement requires ExoticExtendedMarriage. Her biological mother had a nervous breakdown after he killed her brother, and Lewellyn's sister's family took her in as a fourth mother. Also note that in their culture children typically don't know or care which of their father's wives is their biological mother.
* In the ''Literature/{{Deryni}}'' book ''The Bishop's Heir'' said heir abruptly discovers that his parents are his grandparents, that his twin sister is is fact his aunt and that another long dead sister was actually his mother having clandestinely married a young man who later becomes a bishop. The emotional impact of the discovery is cushioned by the fact that the boy has known and been fond of his biological father since he was six, and the fact that he will fall heir to a duchy if they can only prove his parents were legally married probably doesn't hurt.
* Some of the twists in the ''Literature/AbramsDaughters'' series by Beverly Lewis feature this. For instance, Leah Ebersol eventually learns her biological mother is her "Aunt" Lizzie, while her biological father is the local (non-Amish) doctor. Likewise, Jake Mast isn't told until the series' final book that his fiancée is actually his biological aunt.
* ''Literature/CryptidHunters'': Twin protagonists Marty and Grace O'Hara discover that they aren't actually twins; Grace is really Marty's younger cousin, the daughter of Marty's uncle Travis Wolfe and his late wife Rose (Wolfe gave her to his younger sister and her husband to raise after her mother's death, in part because he wasn't able to raise a child on his own and in part to protect her from Rose's father).
* In the ''Literature/SweetValleyHigh'' series, a secondary character is shocked to learn that her "aunt" is really her mother, who lied because she was conceived out of wedlock. As well, in ''The Wakefields Of Sweet Valley'' saga novel, Ted Wakefield is equally shocked to learn the same thing about ''his'' "aunt", who lied for the same reason.
* In ''Literature/WitchesRings'' by Kerstin Ekman, Tora was raised by her grandmother, Sara Sabina, as one of her own children. Unlike many of the examples on this page, this was done to hide a tragedy rather than a scandal: Tora was the result of a pregnancy [[ChildByRape by rape]], and her biological mother was a young teenager who died shortly upon giving birth.
* ''Literature/GirlWaitsWithGun'' is the story of three sisters who live alone on a farm and are harassed by a local criminal. Based on reality, [[spoiler: the youngest sister doesn't know that her grandmother adopted her to avoid the scandal of her own daughter's pregnancy]].
* Occurs twice in ''Literature/TheLightbringerSeries''. The story opens with Gavin finding out he has a bastard son. However, [[spoiler: Gavin is not the real Gavin, but Gavin's brother Dazen in disguise. The real Gavin is implied to be Kip's father, making Dazen his uncle.]] Later on, [[spoiler: it is revealed that their father Andross may actually be Kip's father, making him Gaven and Dazen's half-brother]].
* ''Literature/WeCantRewind'': Mostly back story, but Don grimly notes that being "a grandmother not yet turned thirty" made it pretty easy for Denise's mother to pose as Jaymee's mother too. [[spoiler: Later on, due to a FreakyFridayFlip, Don and Denise are easily able to pass themselves off as the family's children and pass their actual children Jackie and Jaymee off as their parents while getting them married to each other. When Jaymee in her mother's body gives birth to little Jubilee, they decide rather than try to sort out the complicated disparities between her biological and emotional relation to them, they'll just think of her as the ''whole family's'' daughter and raise her together accordingly.]]
* In the ''Literature/OneHundredCupboards'' trilogy, protagonist Henry is sent to live with his aunt (his mother's sister) uncle, and cousins while [[ParentalNeglect his parents are traveling]]. Throughout the course of the story, it is revealed that Henry is a magical DoorstepBaby [[ObliviousAdoption obliviously adopted]] by his MuggleFosterParents... which causes him to suddenly lose his connection to the only loving family he's known, until it is further revealed that his uncle is actually the younger brother of Henry's real father, making his relatives still his aunt, uncle, and cousins, just through the other side.
* In the Colleen [=McCullough=] novel ''The Touch'', it is decided that Elizabeth will serve as her granddaughter Dolly's mother as it becomes quite clear that the child's real mother, her mentally retarded daughter Anna cannot. As both women gave birth at [[AbsurdlyYouthfulMother very young age]]--Elizabeth at 17, Anna at 13--this is completely believable. Unusually, the book ends with Dolly still unaware of her true parentage.

[[folder:Live-Action TV]]
* The ''Series/DoctorWho'' two-parter "[[Recap/DoctorWhoS27E9TheEmptyChild The Empty Child]]"/"[[Recap/DoctorWhoS27E10TheDoctorDances The Doctor Dances]]" involves a young woman who is haunted by a little boy zombified-by-nanotech, who she claims is her brother but turns out to be her son. He is only healed of his zombification after Nancy admits to him that she is his mother, and the nanogenes recognize the literal "mother genes" and heal him and everyone else based on their new knowledge. Prior to this he'd been walking around spreading TheVirus and calling out "Are You My Mummy?" (and being [[CreepyChild pretty damned creepy]] while doing so), hence the former trope name.
* Spinoff ''Series/{{Torchwood}}'' gets into the act as well. Captain Jack Harkness (who was introduced in the above ''Doctor Who'' two-parter, and who has since become {{immortal|ity}}) ends up masquerading as his daughter's "brother" once she grows up -- she knows, but her son (Jack's "nephew"/grandson) doesn't.
* ''Series/DesperateHousewives'' : Bree hides the pregnancy of her teenage girl and pretends to be the mother of her grandson.
* ''Series/EastEnders'':
** The following famous interchange between the Slater "sisters" (though TheReveal for the audience had happened a few months before, this was when Zoe found out). This was due to rape, Kat had been raped by her uncle at 13.
--->'''Zoe Slater:''' You can't tell me what to do, [[YoureNotMyFather you ain't my muvver!]]\\
'''Kat Slater (Zoe's "sister"):''' ''Yes I am!''
** More recently, a storyline revealed that Shirley Carter's brother Mick was really her son.
* After her irresponsible sister abandons her daughter, ''Series/{{ER}}'s Susan Lewis becomes the baby's foster mother and is in the final stages of formally adopting her and becoming her legal mother despite actually being her aunt when her sister resurfaces, having finally cleaned up her act.
* In ''Series/PrincessReturningPearl'', for a long time, it was kept a secret that [[spoiler: Xiao Jian was Xiao Yan Ziís brother, and the person who basically caused their entire familyís death is Qian Long, who is not only Xiao Yan Ziís adoptive father but also the father of her sworn sister and best friend, and of her fiancé]]. There is a big [[{{TheReveal}} reveal]] eventually that basically accummulates to become a DramaBomb.
* Similarly on ''Series/{{Playing the Field}}'', a BBC TV drama series about a women's football team. It fairly quickly wound up as a series about sex, relationships, and Aren't Men Awful, and this trope naturally turned up in due course: two of the team members were actually mother and daughter and not sisters as the younger one thought. (The mother wasn't raped, except in the statutory sense; she had an under-age but fully consensual affair with a much older man, and refused to identify him when she fell pregnant. Naturally, he's about the place in the series too.)
* Happened in an episode of ''Series/{{Millennium}}''.
* The Janitor in ''Series/{{Scrubs}}'' claims to have made several traumatic discoveries along these lines. He's a compulsive liar, though.
* Occurred in the ''Series/{{CSI}}'' episode "Blood Drops," although the child in question is not privy to TheReveal.
* At the end of the first season finale of ''Series/PushingDaisies'', [[spoiler:Chuck's aunt Lily claims to be Chuck's mother. Chuck herself becomes aware of this early in season 2.]]
* In the final season of ''Series/TheSopranos'', it is revealed that [[spoiler: Paulie Walnuts has been raised by his aunt his entire life, because his mother was a nun who broke her vow of chastity with an American soldier.]]
* Subverted in ''Series/{{Rome}}''. When Niobe's husband comes back after years of absence to see her holding a baby she has some explaining to do. She claims it's the son of their 13 year old daughter. Given how well the secret was kept it seems they must have kept the neighbours in the dark too and planned the substitution from the start, or invoked this trope.
* An episode of ''Series/Numb3rs'' revolving around a polygamist cult features a pair of women who are sisters ''and'' mother and daughter (unknown to the daughter until some way into the episode).
* The 1990 TV miniseries version of ''Series/ThePhantomOfTheOpera'', with Creator/CharlesDance. In it, it is revealed that the Opera House's old manager is Erik's father, but he has pretended to be a more distant relative, "out of cowardice". Towards the end, he reveals the truth to Erik, who in a slight subversion says he'd known it, and wondered when he would tell the truth. The same thing happens in the Yeston-Kopit musical version, which had the same writer.
* Oddly enough, {{played for laughs}} -- sort of -- in ''Series/ThirtyRock'''s Valentine's Day episode, as the capstone to the worst first date ever.
* On ''Series/VeronicaMars'', Jackie's "younger brother" is revealed to be her son -- a fact he is not aware of, as he calls his grandmother "mom".
* In the Australian soap ''Series/HomeAndAway'', Charlie is revealed to be Ruby's mother, born after Charlie was raped. Charlie's parents raised the baby as their daughter. When Ruby finds out, she goes ape about it, before finally forgiving Charlie for the deception.
* A major arc on ''Series/{{Moesha}}'' involves Dorian discovering that his uncle, Frank, is really his biological father, born from a relationship he had while he was separated from his first wife. His mother was thus really his aunt.
* On ''Series/TheParkers'' (a spin-off of ''Moesha,'' above), Nikki is shocked to discover (on a family trivia {{game show}}, no less) that she was adopted. Her biological mother turns out to be her aunt.
* Occasionally encountered in ''Series/LawAndOrderSpecialVictimsUnit''. Fin's nephew, and cousin of Fin's son Ken, Darius (played by Ludacris) forces Finn's ex-wife to reveal in court that he is actually her son, a half-brother to Ken, the result of being [[ParentalIncest raped by her own father]]. He was raised by his grandmother, who [[DeathbedConfession told him on her death bed]].
** In another episode, they found out the adopted son of a judge was actually his ''biological'' child via his stepdaughter, who he'd raped when she was eleven.
* Original ''Series/LawAndOrder'' has it in the episode "Merger" in 1999, where [[spoiler: the teenaged murder victim was the daughter of the wealthy family's older child, and not a sister]]
* In ''Series/{{Supergirl}}'', Lena Luthor is introduced as the adopted sister of [[Franchise/{{Superman}} Lex Luthor]]. About halfway through the season, her adopted mother reveals that her "adoptive" father is also her biological father. He'd had an affair and adopted Lena after her mother died.
* In the ''Series/CriminalMinds'' episode "Taboo," the unsub knew he was adopted. What he didn't know was that his "older sister" was actually his mother, who'd gotten pregnant at sixteen. He grew up attracted to his "sister," because he believed they weren't biologically related, so it would be okay for them to have sex. Finding out the truth led him to snap.
* In ''Series/{{Neighbours}}'', Lyn Scully discovered that her Aunt Valda was actually her mother, who had gotten pregnant with her at a young age and been forced by her family to give baby Lyn to her older, married sister.
* ''Series/{{Godivas}}'': A secondary character named Chantal shows up to stay with Simone, her estranged older sister. Turns out Simone is actually her mother. (Coincidentally, Simone "deflowers" a young busboy named TJ in a much earlier episode -- the same TJ that Chantal now starts dating.)
* ''Series/{{Frasier}}'' discussed this trope when Roz got pregnant and decided to raise her kid on her own.
* On ''Series/TheVampireDiaries'', [[spoiler:Elena]] learns that her uncle is actually her biological father; she was born when he was a teenager, and after the mother left town, he gave his daughter to his much-older brother and his [[ButICantBePregnant supposedly infertile]] wife to raise as their own child.
* On ''Series/OneLifeToLive'', Destiny Evans was raised by her paternal grandparents, but believed they were her parents. She later learned that her real father was her "older brother" Greg, who accidentally killed her mother Charlene, the girlfriend of his brother Shaun, and then gave Destiny to his parents to raise.
* On ''Series/GeneralHospital'' it was revealed that Claudia Zacchara was not actually Johnny Zacchara's sister but his mother, making Anthony Zacchara his grandfather (his real father was Gino).
* Double for the money example in ''Series/ChinesePaladin'': Ah Nu discovers that her sensei is actually her mother, and [[LukeIAmYourFather discovers her long-lost father's identity at the same time.]]
* In ''Series/TimeGentlemenPlease'', it is greatly implied that the Guv's "Uncle" Barry is actually his real father.
* In ''Series/{{Emmerdale}}'' Rishi Sharma decides to pretend he's the father of his son Jai's child with Rachel Brickle to save Jai's marriage his wife Charity by covering up the fact that Jai had a brief one night stand affair with Rachel. In this case however it doesn't take all of the stigma away from the situation, given that the child is still known to be the result of an extra-martial one night stand anyway, but it just means that as Rishi's marriage is already in the gutter anyway he thought it would be better to protect his son Jai.
* In ''Series/LabRats'', Adam, Bree and Chase are under the impression that Donald is their [[ArtificialHuman biological]] dad. They find out that he's really their uncle who adopted them because their real dad, his brother Douglas, [[EvilutionaryBiologist created them to be weapons.]] They also find out that Marcus, who they thought was just a classmate turned enemy, is really their brother as Douglas is his father too.
* In one episode of ''Series/TwoPointFourChildren'', Rona's about to lose her council house unless she can provide her birth certificate to have the tenancy transferred to her as the daughter of the previous tenant. The birth certificate forces "Aunt" Pearl to reveal that ''she'' is Rona's real mother, but Rona grew up with Pearl's childless sister and brother-in-law since Pearl wasn't married at the time.
* ''Series/{{Justified}}'': Kendal Crowe is introduced as the youngest brother of the family; he's actually the son of his "sister" Wendy.
* In ''Series/{{Hollyoaks}}'', Peri Lomax turns out to be her "sister" Leela's daughter, raised by her grandparents Sam and Danny as their own daughter because Leela was only fourteen years old and the father, Cameron, was a dangerous criminal ([[spoiler: whom Sam framed for murder in order to keep him away from the family.]]) However, Peri continues to consider Sam and Danny her real parents even after the truth is revealed.
** There have been at least two cases on the show of cousins turning out to be siblings because of parental affairs: Rhys Ashworth is actually Josh and Hannah's half-brother, and Kathleen [=McQueen=] claims that she slept with Jacqui and Mercedes's father meaning Theresa is their sister as well as cousin (although whether she was telling the truth is questionable.)
* In the pilot of ''Series/{{Endeavour}}'', a murdered girl's "older sister" is revealed to have secretly been her mother. This becomes relevant when she [[spoiler: discovers that the girl's father had gotten the girl involved with a sex ring, and beats his brains in with a crowbar]].
* Discussed in an episode of ''Series/ModernFamily'', where Alex asks her mother if this would happen if her older teenage sister got pregnant from her boyfriend.
* ''Series/GameOfThrones'':
** Since Season 1 we have the knowledge that Jaime Lannister is actually the father of Joffrey, Myrcella and Tommen, instead of their uncle ([[{{Squick}} though he's also that too]]) due to BrotherSisterIncest.
** Like it's hinted in the books, [[spoiler:Season 6 confirms that Ned Stark passed Jon Snow off as his bastard son instead of his nephew (Jon being his late sister's son) to conceal his Targaryen legacy from Robert Baratheon.]]
* ''Series/{{Tyrant}}'': Leila reveals to Cameron that she had an affair with Barry, who is really his father, but let Jamal think he was his.
* ''Series/MurderSheWrote'': In "Unauthorized Obituary", Jessica discovers that the sister of the VictimOfTheWeek was really her daughter, with the mother having given birth when she was fifteen. This explains why she was so protective of her 'sister'.
* ''Series/MidsomerMurders'': In "Death and the Divas", it is revealed that when a younger sister had an illegitimate baby, her older married sister registered the baby as hers and raised the girl as her own.
* ''Series/BeverlyHills90210'': [[RememberTheNewGuy Gina]] was introduced in the show's ninth season as Donna's cousin, and caused much havoc within the group. In season 10, the audience discovered that Donna's father had an affair with Gina's mother in the 1970s, resulting in her birth, making Gina her half-sister in addition to being her cousin. Donna's father, Dr. Martin, discovered this, and was quick to accept Gina as his daughter, though [[spoiler: he later died soon after accepting her into the Martin family]].
* In ''Series/{{Patriot}}'', Efram is Edward's biological son, but has been raised to think of Edward as a Big Brother-type mentor, because Edward is a Senator and might lose his job if people found out that he had a kid out of wedlock.
* The FirstEpisodeSpoiler for ''Series/AndiMack'' is that Andi's "sister" Bex is really her mother.
* ''Series/{{Endeavour}}'': In "Pilot", the VictimOfTheWeek is a teenage girl who is actually the daughter of her older 'sister'. The 'sister' had gotten pregnant as a teenager and her parents had taken the child on as their own so she would not ruin her life.
* One episode of the court show ''Series/AnaRules'' involved a teenage girl asking to live with her sister instead of her overprotective mother. As it turns out, her sister was really her biological mother. She had her at age fourteen so her mother decided to raise the baby as her own instead.
* ''Series/{{Vera}}'': In "Protected", this kind of relationship lies at the bottom of the murder. The VictimOfTheWeek was actually the son of his elder 'sister'; having been born when she was 15. Although estranged from her family, and married with a family of her own, she remained close to her son. She finally tells him the truth, which sets in motion the chain of events that results in his murder.

[[folder:Stand-Up Comedy]]
* Creator/ChrisRock has a bit about this, saying "If the kid calls his grandmama 'Mommy' and his mama 'Pam', then he's going to jail."

* ''Theatre/TopGirls'' by Caryl Churchill: [[spoiler:Angie is really Marlene's daughter, but was raised as the daughter of Marlene's sister Joyce. Poignantly played upon in the last scene when Angie calls for her mother and Marlene responds "No, it's Aunt Marlene."]]

[[folder:Web Comics]]
* In ''Webcomic/{{Drowtales}}'', it turns out that [[spoiler:Ariel]] is not really [[spoiler:Quain'tana's]] daughter, but is actually [[spoiler:Mel'arnach's]], who she's been raised to think of as a sister. And just to further complicate matters, [[spoiler:Ariel's father is Zhor, a dark elf who was transformed into a frickin' ''giant spider'']].
* ''Webcomic/{{Homestuck}}'': Quite a few examples, due to ectobiology (i.e., cloning) and TimeTravel mismatching generations and ages.
** Dave's older brother [[spoiler:is actually his genetic father. Ironically, Bro Strider is about the same age as Mom Lalonde, making it all the stranger that he tells Dave they're brothers instead of father and son]].
** Jade's grandfather [[spoiler:is actually her genetic father. John's [[PostHumousCharacter long-dead grandmother]] is his genetic mother and his father is actually his half-brother]].
** Averted with Rose: Mom Lalonde IS her genetic mother.
** And then [[spoiler:after the scratch, we have the original kids swapped with their genetic parents. Jane Crocker was raised by Dad, [[TangledFamilyTree whose exact genetic relation to her is unclear]]. Jake was adopted by his genetic daughter, Jade, who called herself his grandmother. Dirk and Roxy refer to their genetic son and daughter respectively as older brother and mother. [[TimeTravel Time]] [[PrecisionFStrike fucking]] [[TimeParadox shenanigans]].]]
* In ''Webcomic/DragonCity'', [[spoiler: Beatrix's case is a little different. She and her "older sister" Erin traveled back in time to when Beatrix's egg was laid. It was at this point that Erin lays Beatrix's egg, though she ends up getting raised by their mother of that time period (who mistook it for one of her own eggs).]]
* ''Webcomic/ShotgunShuffle'' has oldest daughter Ginger adopt middle daughter Juniper's son after Juni's teenage pregnancy. (And by "middle", we mean "4th of 7", not "2nd of 3".)

[[folder:Western Animation]]
* One episode of ''WesternAnimation/TheSimpsons'' has Bart (pretending to be older) date a fourteen-year-old girl who turns out to be pregnant. After being assured he ''can't'' be the father ("Wow, you ''are'' only ten") [[GiveTheBabyAFather he agrees to marry her anyway]] to hide the truth. When the girl's parents find out the mother announces that ''she's'' pregnant too, and the family ([[StepfordSmiler with sort of creepy cheerfulness]]) agree to pretend the mom has twins. It is therefore implied that TheReveal will occur some years later.
* ''WesternAnimation/TheVentureBrothers'' has the reveal that [[spoiler:Dermott is the son of Rusty Venture and the fifteen-year-old president of his fanclub]], and was raised by the mother of his biological mother.
* Discussed in ''WesternAnimation/TheClevelandShow'':
-->'''Donna:''' This isn't going to be easy to hear...\\
'''Rallo:''' Roberta's actually my mother?\\
'''Donna:''' Don't ever say that again!
* In ''WesternAnimation/AdventureTime'', it is revealed that [[spoiler:Jake's mother actually had no blood relationship to him, and he was conceived when his father was [[FaceFullOfAlienWingWong attacked]] by an EldritchAbomination and had a child grow parasitically on him that apparently shared his genetics. This is the true origin of his [[RubberMan powers]], and not falling into a magic puddle as a baby as his parents told him.]]

[[folder:Real Life]]
* Up until the 1970s (when the Pill and legalized abortion became available and cohabitation became acceptable) it was common for young women pregnant out of wedlock to be "sent away" before they started to show and to give birth in secret. "Homes for wayward girls" were essentially private maternity wards where women were heavily pressured to give their children up for adoption (as long as they were white--at the time the adoption prospects for nonwhite babies were...pretty grim). Birth mothers might not even be allowed to ''see'' their babies before they were taken away to the adoptive parents. Faced with losing her child forever, it's not hard to see why a mother might prefer becoming an "older sister" who could still be part of the child's life. ''The Girls Who Went Away'' by Ann Fessler is a good source for those looking to learn more about maternity homes and forced adoption. While many children of young unwed mothers are still raised by their grandparents, it's much less common for families to bother concealing the underlying biological relationships.
* Jack Nicholson's "older sister" was really his mother while the woman who was allegedly his mom was actually his grandmother. His real mother did it because she had sex with a man (both were unmarried) who ended up leaving her and she didn't want anyone to know that she was an unwed mother (both Nicholson's grandmother and mother died before he found out this family secret). In a height of coincidence, he learned this just as ''Film/{{Chinatown}}'' -- in which he starred -- was about to open in theaters.
* Music/EricClapton was born when his mother, Patricia Clapton, was 16 years old; his father was a Canadian soldier who shipped off to UsefulNotes/WorldWarII before Eric's birth and then went back to Canada. He was raised believing Rose and Jack Clapp, his mother's mother and stepfather, were his parents.
* Music/BobbyDarin's mother, Nina Cassotto, was 17 and unmarried when he was born, and he grew up thinking his parents were Nina's parents (even though her father died of pneumonia a year before he was born) and that Nina was his older sister. He didn't learn the truth until he was 32 years old, and the identity of his biological father remained a very closely-guarded secret right up to Nina's death in 1983.
* Australian singer David Campbell's real father was Jimmy Barnes, who would go on to become an Australian rock icon, but he was raised by his mother's parents, believing them to be his own parents.
* Serial killer Ted Bundy suspected for years that his older sister was in fact his mother, finally learning it for a fact in 1969. Even worse, she might very well ''have'' been his sister after all, given the heavy, yet unproven speculation that he was the result of ParentalIncest between her and his grandfather.
* Civil Rights/gay rights activist Bayard Rustin grew up believing Janifer and Julia Rustin, the parents of his biological mother Florence Rustin, were his parents and that Florence was his older sister.
* Novellist Catherine Cookson was raised believing her parents were Rose and John [=McMullen=], who were in fact the parents of her real mother, unmarried alcoholic Kate Fawcett (it didn't help that her father, Alexander Davies, was a bigamist and a compulsive gambler).
* Anglo-Indian actress Merle Oberon likely saw no reason not to believe that Charlotte Selby was her mother, as she was only in her mid-twenties when Oberon was born. However, her real mother was Selby's illegitimate daughter Constance, who had been born when Charlotte was fourteen years old and whom Oberon believed to be her sister; Oberon herself had been born when Constance was ''twelve'' years old. Her father was listed on her birth certificate as Charlotte's partner Arthur Thompson, but he was neither her father nor her grandfather (the latter was an Irish tea plantation foreman named Henry Selby).
* Literature/GuinnessWorldRecords refuses to accept many well-known historical claims for "oldest mother to successfully carry a child to term" out of suspicion that they were examples of this trope.
* [[http://en.wikipedia.org/wiki/Kidnapping_of_Jaycee_Lee_Dugard Jaycee Lee Dugard's]] two daughters, (ages 15 and 11) by her rapist and kidnapper Phillip Garrido believed their whole lives that Jaycee was their older sister and that Garrido's wife was their mother. They had to find out the horrible truth after the police finally caught and arrested Garrido.
* Upon the announcement of her candidacy for Vice-President of the United States in the 2008 elections, rumours began to circulate that Gov. Sarah Palin was actually the grandmother of her youngest son, and that his oldest sister was actually his mother. Subverted, as the rumours were soon proved completely unfounded; one of the giveaways was that the boy, Trig, had Down's Syndrome, which is ''far'' more common with older mothers. Her eldest daughter, Bristol, would later get pregnant out of wedlock, but the Palins decided to be public about it.
* In the Middle Ages it was not unusual for popes to have illegitimate children (such as [[http://en.wikipedia.org/wiki/Pope_Alexander_VI Pope Alexander VI]]'s children, Cesare and Lucrezia Borgia) that they bestowed favors upon, although it was considered gauche to publicly acknowledge their paternity. Instead, they were referred to as "nephews" or "nieces" of the pope. This is the origin of the term "{{Nepotism}}".
* In 1939, a then-5-year-old girl from Peru named [[http://www.snopes.com/pregnant/medina.asp Lina Medina]] was taken to the hospital for a tumor in her belly. During the examination, it turned out that she was ''pregnant'' (she had gone through puberty at an ''unusually'' early age). She gave birth via c-section to a young boy, but was told her whole life that he was her younger brother. It is not known who his father was; Lina's father was jailed on suspicion of incest, but he was released for lack of evidence, and Lina herself wouldn't say who had done this to her. She lived a pretty normal life otherwise, and later married and had another son (this time one that she actually knew was her son.)