History Main / NotBloodSiblings

* This was brutally parodied in ''Film/NotAnotherTeenMovie'' when their Kathryn expy constantly tries to seduce her brother.

* ''Series/ASmallLight'': Miep's adoptive parents bring this point up when they suggest her marrying Cas. Neither Miep or Cas are supportive of this idea, especially since Cas is a closeted homosexual.

* A very strange example in ''Series/SixteenAndPregnant'' (and spin-off ''Teen Mom''): couple Catelynn and Tyler are stepsiblings because Catelynn's mom April and Tyler's father Butch are married. Butch and April met and married ''after'' their children started dating.

* In ''Anime/MagicalGirlLyricalNanohaStrikers'' the [[ShipTease hinted-at]] ToyShip of Erio and Caro may sort of fit this in that Fate ends up being the legal guardian of both (though Erio is technically under the custody of Fate's adoptive mother Lindy due to her having been too young to put her name on the paperwork). The accompanying ''[=StrikerS=]'' manga has them repeatedly state that they are technically adopted siblings... while lathering on even more ShipTease. Unlike other non-blood siblings, they had never met prior to ''[=StrikerS=]'', and had no pre-existing sibling relationships (they even begin on a LastNameBasis).

As for reality, it depends. These tropes tend to gross out anyone who has been raised alongside their stepsiblings. If they met as teens or later, though, it can seem unfair that their parents got together before they did.

* [[spoiler:Hiro and Karada]] in ''Manga/LivingForTheDayAfterTomorrow''; not taken to a romantic end, but still important to the plot. It's implied in the manga (but left unmentioned in the anime) that [[spoiler:while not siblings, they ARE blood-related, but Karada never knows (she would be the daughter of Hiro and his aunt conceived just before he went to study in the US).]]
* Eren and Mikasa in ''Manga/AttackOnTitan'' is more {{Justified}} than some examples, since his family took her in when she was already nine. While Eren doesn't seem to have any romantic feelings towards Mikasa, Mikasa loves Eren to the point that she's willing to die for him, and EveryoneCanSeeIt.

** In the books by the infamous ghostwriter Andrew Neiderman, it's actually more common for the heroine to end up with a man she initially believes is her brother/half-brother/cousin until it's revealed that they are not actually blood-related, making it fine for them to marry each other. The best example of this is the Literature/CutlerSeries where Dawn learns that she's actually adopted and that Jimmy is hence not really her brother; Jimmy even expresses his relief about this as he was attracted to Dawn even when he thought they were related. (And just to top this all off, Dawn's original boyfriend Philip turns out to be her ''actual'' brother who remains obsessed with her after the truth of their relations comes out to [[LoveMakesYouEvil absolutely creepy levels]].) Other examples are Heaven's daughter Annie and apparent half-brother Luke from Literature/TheCasteelSeries, Melody and apparent cousin Cory from the ''Literature/LoganSeries'' (okay, it turns out they're [[KissingCousins still blood-related]] but only as second cousins, which makes marriage between them legal), and Rain and apparent brother Roy from the Literature/HudsonSeries (although they don't end up together, and there's that thing about Rain's own blood brother being attracted to her too -- she doesn't end up with him either, thank goodness).

* Parodied in the ''Manga/KaguyaSamaLoveIsWar'' bonus chapter "Kagukoku: Miyuki and His Girls", where Shirogane wakes up to find himself in a generic harem series. Naturally, his little sister Kei is cast as the step-sister with a brother complex who lives alone with him while their parents work overseas.

For when "siblings" are by choice, instead of blood, that's FamilyOfChoice. Also, do not forget that the ever-growing number of imouto-titles has practically translated this trope into the category LikeYouWouldReallyDoIt and CaptainObviousReveal, so even its well-founded use can very quickly get into ClicheStorm. Not Blood Siblings is to BrotherSisterIncest as FauxInterracialRelationship is to MalignedMixedMarriage. Not to be confused with BloodBrothers, where unrelated characters make a pact and become like siblings. Also, see WifeHusbandry for when this trope is taken to an even squick-ier level. For the inverted version -- people who find out they're related after thinking they're not -- see SurpriseIncest. See also NotBloodNotFamily for cases where a person is excluded as family due to lack of blood ties.

* ''Literature/TheMissing'': Invoked by Chip after he learns that Jonah is adopted and Jonah's sister Katherine isn't. Chip asks Jonah if he (Jonah) and Katherine can date. Jonah considers Katherine to be his sister and is grossed out by the idea.

For when "siblings" are by choice, instead of blood, that's FamilyOfChoice. Also, do not forget that the ever-growing number of imouto-titles has practically translated this trope into the category LikeYouWouldReallyDoIt and CaptainObviousReveal, so even its well-founded use can very quickly get into ClicheStorm. Not Blood Siblings is to BrotherSisterIncest as FauxInterracialRelationship is to MalignedMixedMarriage. Not to be confused with BloodBrothers, where unrelated characters make a pact and become like siblings. Also, see WifeHusbandry for when this trope is taken to an even squick-ier level. For the inverted version -- people who find out they're related after thinking they're not -- see SurpriseIncest.

Therefore, in such cases, the story adaptations usually omitted the siblings relationship and the characters almost never treat each other as LikeBrotherAndSister, so as not to cause unpleasant associations in more conservative times.

** It is eventually revealed that [[spoiler:Shinji Matou [[MoralEventHorizon has been]] [[RapeIsASpecialKindOfEvil regularly raping]] his adopted sister [[TheWoobie Sakura]]]].

* ''Literature/SadCypres:'' Roddy and Elinor are raised as cousins and have been sweethearts for a long time, but are only related due to the marriage of Roddy's uncle to Elinor's aunt. Roddy later dumps Elinor to pursue Mary Gerard, but still has some feelings for her.
** ''Literature/TheStressOfHerRegard'': after the death of his wife, the protagonist is MistakenForMurderer by her AngstySurvivingTwin. She later comes to accept that he is innocent of the crime, and for years they work together (and pass for) brother and sister. When at a later point they have to pass as husband and wife, there are complications.

* On ''Series/DarkAngel'', Max and the rest of her X5 unit consider each other siblings because they were "raised" together, although they don't share genetics. Their only biological siblings are their clones, who were in different units. (Creator/JessicaAlba's real-life brother Joshua does play Max's brother Krit, but it's unclear this is meant to imply their characters share DNA.) Zack falls in love with Max, and it {{Squick}}s her out. She wasn't too sanguine about the idea of being breeding partners with Alec, the twin of her brother Ben, either.

For when "siblings" are by choice, instead of blood, that's FamilyOfChoice. Also, do not forget that the ever-growing number of imouto-titles has practically translated this trope into the category LikeYouWouldReallyDoIt and CaptainObviousReveal, so even its well-founded use can very quickly get into ClicheStorm. Not Blood Siblings is to BrotherSisterIncest as FauxInterracialRelationship is to MalignedMixedMarriage. Not to be confused with BloodBrothers, where unrelated characters make a pact and become like siblings. Also see WifeHusbandry for when this trope is taken to an even squick-ier level. For the inverted version -- people who find out they're related after thinking they're not -- see SurpriseIncest.

* Few ''Westernanimation/OneHundredAndOneDalmatianStreet'' fanfics often use this excuse to pair up Dolly and Dylan together, they are confirmed to be stepsiblings by the original creators but there is nothing suggesting it in the show itself.
* ''WesternAnimation/PhineasAndFerb'' often fall into this; they're canonically stepbrothers, but ''refer'' to each other as brothers and have been raised together since they were toddlers. Slightly less commonly they'll be paired with their older sister (biological for Phineas, step- for Ferb) Candace.
* ''Series/DrakeAndJosh'' has a few examples between the titular stepbrothers.
* ''WesternAnimation/InvaderZim'': There are not very many [[HeroAntagonist Dib]]/[[CreepyChild Gaz]] shippers, but the few fics you'll find of it tend to use the WordOfSaintPaul concept of Dib being an ArtificialHuman to justify it. A particularly popular idea is that Dib is a clone of [[ReluctantMadScientist Membrane]] and Gaz is a clone of his [[AmbiguouslyAbsentParent unseen, presumably-dead wife]].
* ''Series/LifeWithDerek'':
** Derek and Casey is a non-canon ship that's largely popular with the fanbase, as opposed to all the other love interests that are introduced throughout the series. The fact that half of the show focuses on the interactions and the relationship between the two stepsiblings doesn't help.
** As a sort of [[BetaCouple Beta]] FanPreferredCouple of sorts, there's also Edwin and Lizzie, the younger siblings of Derek and Casey respectively. Doesn't help that both sometimes use the closet as a meeting place, which immediately has shippers thinking of the TenMinutesInTheCloset trope.
* Many ''Literature/TheChroniclesOfNarnia'' fans use this excuse in [[BrotherSisterIncest Edmund/Lucy and Peter/Susan]] stories.

* ''Twilight'' fic "[[https://www.fanfiction.net/s/4668040/1/Bella-Hale Bella Hale]]" sees Alice taking steps to avoid this as much as possible after the Cullens adopt a six-year-old Bella following her parents' deaths. As soon as Alice sees a vision of Bella and Edward together in the future, she takes subtle steps so that Bella is listed on paper as Rosalie and Jasper's direct sibling, thus creating a sense of distance so that her future relationship with Edward won't seem quite as weird.
* Even though ''Toys/{{Bionicle}}'' is supposed to be a NoHuggingNoKissing universe, (any romantic subtexts in the movies are [[CanonDisContinuity discontinuities]]) there's a good deal of romance in FanFiction. A lot of it is between members of the same team who call each other "brother" and "sister". However, it becomes much less {{squick}}y when you realize that the entire cast is made of [[WhatMeasureIsANonHuman mostly machine cyborgs]] and that "brother" is more a title of endearment than anything.

* In one ''Manga/{{Naruto}}'' fan comic, Temari discovers her father's secret papers, which prove that she was actually adopted, and doesn't have to hide her feelings for her younger brother Gaara any longer. Kankuro then wonders if he can do the same for Gaara, but Temari beats him up while reminding him that he and Gaara are still related, since ''she's'' the one who was adopted.
* ''Fanfic/OneiroiSeries'': Terentius briefly tries to use this rationale to excuse himself from wanting [[BrotherSisterIncest his adopted half-sister]], but he quickly breaks down, admitting to himself that it really doesn't matter and that he was lusting after his little sister.
* Subverted in ''Fanfic/RelationshipsSeries''. When it comes to light that Nove and Ginga, who are in a three-way relationship with each other and Wendi, are genetically related, this revelation [[spoiler:motivates Genya's decision to send Ginga on a mission to separate her from Nove and Wendi]].

* The ''Franchise/StarWars'' fanfic "[[https://www.fanfiction.net/s/3503810/Father-and-Son Father and Son]]" has Han and Leia as a couple (as in canon) despite the fact that her (and Luke's) birth parents adopted and raised Han for several years before the twins were born. Somehow, nobody (not even Vader or Padme's extended family on Naboo) sees anything wrong with the two being a couple. (Admittedly, all three siblings were sent to separate planets after Anakin's FaceHeelTurn and Padme's DeathByChildbirth and didn't find out that they were siblings until after they were all adults. But still.)
* Most fanfiction for the pairing of Shadow the Hedgehog and Maria Robotnik from ''VideoGame/SonicTheHedgehog'' downplay the LikeBrotherAndSister aspect their relationship may or may not have had. The fact that they're [[ExaggeratedTrope not even the same species]] certainly lends weight to the argument against any romantic relationship being incestuous... Although for some people that might just [[MalignedMixedMarriage create another reason to be against it.]]
* Thor and Loki of the Marvel universe tend to be the subject of some arguments regarding whether or not pairing them constitutes incest. On the one hand, they were raised together and usually refer to each other as brothers (albeit somewhat sarcastically), but being that Loki is an adopted frost giant and goes by Laufeyson and not Odinson, whether or not they see each other as siblings depends on the writer.
* A few ''WesternAnimation/YinYangYo'' fans use this to justify the {{Twincest}}.
* A source of some discomfort to Shinji in ''Fanfic/DoingItRightThisTime''. First he had what he thought was a near-miss with SurpriseIncest before the whole PeggySue thing happened, but now it turns out Rei wasn't a clone of who everyone thought she was and they're definitely not even siblings by adoption ([[YouAreNotMyFather Rei's pretty emphatic about that]]) and he has no idea if that makes the time he accidentally saw her naked better or worse. Especially because [[LoveTriangle he has a bit of a thing for Asuka as well.]]
* As the quote above demonstrates, ''WebVideo/FriendshipIsWitchcraft'''s [[WesternAnimation/MyLittlePonyFriendshipIsMagic Twilight Sparkle]] justifies having a crush on her brother Francis (that universe's version of Shining Armor) by pointing out that Francis was a DoorstopBaby left at Twilight's house. Even after her explanation, the other ponies still find the attraction creepy. [[spoiler:Twilight [[MurderTheHypotenuse wins in the end]], and eventually marries Francis.]]

* Quite a bit of ''Franchise/TeenageMutantNinjaTurtles'' fans who like "Tcest" write the brothers as adopted siblings. It's vague in the various continuities if they're blood-related or not.
* In the ''WesternAnimation/{{Frozen|2013}}'' fanfic ''[[Fanfic/BecomingFree Becoming Family]]'', Elsa's adopted daughter and Anna's biological son fall in love. The [[KissingCousins cousin incest]] element never gets referenced.
* PlayedForLaughs in the ''Series/{{Community}}'' fanfic ''If It's Real (It Stains Your Hands Like Wine).'' During [[Recap/CommunityS6E08IntroToRecycledCinema Abed's crappy movie]], Jeff and Annie almost kiss until Britta reminds them that their characters are supposed to be father and daughter. Abed declares that the movie does need a kiss, however, so they'll just say that Annie is someone else's daughter who was kidnapped as a baby and raised by Jeff. Britta points out that this is ''worse'', but everyone else thinks it's fine. Abed eventually decides they don't have time to film the kiss after all, and it's implied that the only reason he suggested it in the first place was to [[ShipperOnDeck push Jeff closer to Annie]].
* In ''[[https://www.fanfiction.net/s/12200711/1/The-Reign-of-Marco Reign of Marco]],'' Star was adopted as a child by the Diaz family. She takes full advantage of this in the present.
* In ''Fanfic/TheirBond'', Link was adopted by Princess Zelda's father as a child and the two were raised as siblings. As teens, Impa catches the two being intimate but it's [[NotWhatItLooksLike a bit different]] than it initially seems. [[spoiler:Yes, it was sexual, but neither actually wanted it. They're [[IncompatibleOrientation not even attracted]] to the opposite sex. Zelda uses making out with Link as a way of dealing with her past sexual abuse by Ganondorf.]]
* ''Fanfic/ReBoundRWBY'' is a ''WebAnimation/{{RWBY}}'' fic which ships Ruby and Neo. It's revealed several chapters in that Neo is the adopted daughter of Raven, taken in [[spoiler:after Raven's tribe killed six-year-old Neo's parents]]. Raven is the biological, absentee mother of Ruby's paternal half-sister Yang. So they're both half-sisters to Yang in a sense, but on different sides of the family tree.
* ''Fanfic/FateHaremAntics'': Shirou is the adopted son of Illya's father. While they didn't grow up together, and Shirou only found out she existed when the War started, Illya still refers to him as "big brother" ([[OlderThanTheyLook despite actually being older than him]]). She ends up as the third person in Shirou's harem, after she kidnaps him and takes him to her castle for some "alone time."
* Similiar to the Thor and Loki example above, there's room for debate as to whether shipping John and Arthur in ''VideoGame/RedDeadRedemption2'' counts as incest. We know John was taken in by the gang when he was twelve, so he was at least a preteen when him and Arthur met (and thus already past several formative years), but that doesn't change the fact Arthur [[BigBrotherMentor played the role of a big brother]] for a good amount of time. They refer to each other in-game as brothers a few times as well, though often begrudingly. Most fanworks make it ''very'' clear the two didn't develop feelings for each other until John was well of age, at least- and others simply put them into an alternate universe where they didn't meet until they were both adults. Also worth taking into account is the fact that Dutch's gang was anything but conventional in terms of societal values and taboos.
* ''VideoGame/{{Undertale}}'':
** Fan works pairing up Asriel and the first human, which would also be a case of InterspeciesRomance. We learn at New Home that the human was essentially adopted by his parents and that Asriel and the human "became like siblings" over time. When we see evidence of just how devoted he was to them though, it can [[IncestSubtext be read as]] a case of PuppyLove by some.
** Fan works pairing up [[spoiler:Frisk and Asriel]] could fall into this, since [[spoiler:Asriel's parents try to take care of the Frisk and offer to adopt them as well]], and accepting the offer is the most popular ending with fans. Fans who want to try to avert this trope can HandWave it by simply setting their work in an ending where [[spoiler:Frisk chose not to stay with Asriel's family]].
** Like the above example, fan works pairing up [[spoiler:Frisk and Chara]] arguably also qualify, since [[spoiler:Frisk can be adopted by the same parents who'd adopted Chara]], and can be downplayed in the same way.
* ''Fanfic/ChildrenOfRemnant'': Blake and Pyrrha are Jaune's adopted sisters, but they are both obsessively in love with him. Pyrrha channels this obsession into devotion and service, but [[EveryoneCanSeeIt it's still obvious she wants to be something more]]. Blake, surprisingly, is romantically but not sexually in love with him; her preferred endgame is that Jaune and Pyrrha get married so that Pyrrha can handle his physical needs while Blake handles his emotional needs. Jaune is mostly oblivious.
* ''Fanfic/OnceUponADecemberNight'': While this version of April and Donatello were raised as brother and sister, both WordOfGod and subtext confirm that this is a "Apritello" fic.
* ''Fanfic/NoMatterWhat'', an ''WesternAnimation/{{Amphibia}}'' story part of the ''Fanfic/FourthLightSeries'', features a [[DiscussedTrope discussed]]/[[JustifiedTrope justified]] case. [[spoiler:Marcy gets adopted by Anne's parents after hers are arrested for threatening her life: Anne and Marcy were dating before this, but they don't have a problem with it since they're not related by blood and [[TruthInTelevision can legally get married one day so long as they prove it, a true fact in the USA]].]]
* ''Fanfic/FrozenWight'': In-universe, PlayedForLaughs. Elsa and Anna are ''extremely'' annoyed to find that an artist has been drawing and writing incestuous stories about them. He insists that they're ''not'' incestuous; they take place in an alternate universe where they're not actually sisters. This excuse doesn't save him from the defamation charges.

::: However, Bart ignores her words. This reasoning doesn't seem to land with him; he doesn't seem to think it makes a difference. Before Bart can move forward in his relationship with Cindy, he first has to make his peace with incest and accept the relationship between his mother and step-father (who ''are'' blood siblings). Only then can he get together with Cindy, knowing that it ''is'' incest and being ok with that.

-->''Elizabeth:''' Brother and sister no longer...

** This was apparently [[JustForPun relatively]] [[https://satwcomic.com/wrong-answer-wrong-question common in Japan]]

* ''Literature/UnderThePendulumSun'': Cathy learns she is a {{Changeling|Tale}}, a replacement for the ''real'' Catherine Helstone, and thus not the blood sister of her beloved brother Laon with whom she has {{UST}}. They soon begin a pseudo-incestuous relationship. [[spoiler:SubvertedTrope when it turns out that was untrue--she's ''not'' actually a changeling, and they actually ''are'' blood siblings.]]