History Main / LawOfInversePaternity

So, Alice is pregnant and caught in the horns of her TriangRelations - she doesn't know who the father is. So, after sufficient tension has been built up, she discovers that her baby's dad is not Bob, [[{{OTP}} her]] and [[FanPreferredCouple the fans']] one true love, but Charlie, the hypotenuse -- her worst nightmare.

* In "{{Nana}}", after [[spoiler: starting a [[OneTruePairing relationship with Nobu]]]], Hachi [[spoiler: sleeps with Takumi]] then discovers she is pregnant. Since she and [[spoiler: Nobu]] practiced safe sex, [[spoiler: Takumi]] must be the father, so she ends up with him.

** Also averted with Rachel's unplanned pregnancy when [[spoiler:the dad is Ross, her one true love, and not her much younger ex-boyfriend]].

* In one episode of ''JohnDoe'' the boy and the title character want him to be the father, but he isn't.
* On ''{{Lost}}'', Sun is worried that the father of her child is the man she had an affair with, rather than her husband Jin's. Juliet helps her confirm the date of conception. [[spoiler:[[SubvertedTrope It's Jin's]].]]

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** Also averted with Rachel's unplanned pregnancy when [[spoiler:the dad is Ross, her one true love, and not the random way too young dude she just broke up with]].

* Subverted on {{Community}}, when Shirley's baby turns out to be [[spoiler: her ex-husband's rather than her one-night-stand Chang's.]]

* Done three times with the same pregnancy on ''{{Neighbours}}''. Bear with me: first Sky was with Dylan, but cheated on him with her art teacher, breaking them up. A few weeks later, Sky has a one night stand with Dylan's brother Stingray, who is also her best friend. Shortly afterwards, she discovers she is pregnant. When Stingray asks if it could be his baby, she says that she wishes he was, but the dates don't add up. As soon as Dylan has accepted he is the father and become excited, a scan shows that the baby is younger than originally thought, making Stingray the father. This destroys the relationships of Dylan and Sky, Stingray and Rachel, and Dylan and Stingray. Then when the baby is born, a DNA test shows Dylan is the father after all - the baby's size is attributed to Dylan's exposure to toxic waste a year older, which later causes Kerry to develop cancer - but Sky's relationship with Dylan is over permanently, and she ends up with Stingray.

* Done three times with the same pregnancy on ''{{Neighbours}}''. Bear with me: first Sky was with Dylan, but cheated on him with her art teacher, breaking them up. A few weeks later, Sky has a one night stand with Dylan's brother Stingray, who is also her best friend. Shortly afterwards, she discovers she is pregnant. When Stingray asks if it could be his baby, she says that she wishes he was, but the dates don't add up. As soon as Dylan has accepted he is the father and become excited, a scan shows that the baby is younger than originally thought, making Stingray the father. This destroys the relationships of Dylan and Sky, Stingray and Rachel, and Dylan and Stingray. Then when the baby is born, a DNA test shows Dylan is the father after all- but Sky's relationship with Dylan is over permanently, and she ends up with Stingray.

** Used in the movie ''Bender's Game''. The father of Mom's son [[RalphWiggum Igner]] turns out to be none other than [[spoiler:Professor Farnsworth, one of the smartest men in the universe, who is constantly complaining about how stupid Igner is]].

[[AC:{{Literature}}]]
* This happened in ''OedipusRex'' after Oedipus learned that he was adopted. The Oedipus myth itself is OlderThanDirt.

* PlayedWith on ''LivingSingle''--Max gets pregnant by a sperm donor, and later discovers that, by ContrivedCoincidence, the donor was Kyle, with whom she had a major SlapSlapKiss, [[FriendsWithBenefits Enemies With Benefits]]-type relationship before he left the country. The finale has him come back, find out and agree to raise the child with her.

* Played with in ''SomethingPositive:'' [[JerkWithAHeartOfGold Davan]] ''doesn't'' want to be [[BrattyHalfPint Rory]]'s biological father, but while he's willing to step up, the other (unnamed, unseen) guy isn't. Even when Davan is cleared by a DNA test, he becomes Rory's ParentalSubstitute anyway. In a more recent strip he's admitted that in retrospect, he wishes Rory had been his son.

* This happened in ''OedipusRex'' after Oedipus learned that he was adopted. That's OlderThanDirt.

OlderThanDirt.

* This happened in ''OedipusRex'' after Oedipus learned that he was adopted.

* PlayedWith on ''LivingSingle''--Max gets pregnant by a sperm donor, and later discovers that, by ContrivedCoincidence, the donor was Kyle, whom she had a major SlapSlapKiss, [[FriendsWithBenefits Enemies With Benefits]]-type relationship before he left the country. The finale has him come back, find out and agree to raise the child with her.

* Played with in ''SomethingPositive:'' [[JerkWithAHeartOfGold Davan]] ''doesn't'' want to be Rory's biological father, but while he's willing to step up, the other (unnamed, unseen) guy isn't. Even when Davan is cleared by a DNA test, he becomes Rory's ParentalSubstitute anyway. In a more recent strip he's admitted that in retrospect, he wishes Rory had been his son.

* Subverted in ''{{Futurama}}'': Kif's species can get pregnant just by coming in contact with another's DNA; the person whose DNA he assimilated ([[spoiler:Leela]]) wasn't his first choice, but at least it wasn't [[FakeUltimateHero Zapp Brannigan]]. However the parent, or smizmar, is considered to be the one who got them turned on into DNA assimilation mode in the first place, who in this case happens to be Amy.
** Used in the movie ''Bender's Game''. The father of Mom's son [[RalphWiggum Igner]] turns out to be none other than [[spoiler:Professor Farnsworth, one of the smartest men in the universe, who is constantly complaining about how stupid Igner is]].
* Brazilian SoapOpera ''Por Amor'': the main "villainess" raised her two sons very differently because she believed that her favorite one was the one she bore with the man she was and still is truly in love with... who, incidentally, [[YourCheatingHeart isn't her husband of 30 years]]. All the men involved learn about it, DNA tests ensue, and it's revealed that the biological son of her true love was TheUnfavorite. Cue her being abandoned by her family and her ex-lover, and a VillainousBSOD.
* This happened in OedipusRex after Oedipus learned that he was adopted.
* This came into play in SnowDogs (starring Cuba Gooding, Jr.) Our protagonist goes to Alaska to find his real father. He develops mutual hate at first sight with an old and mean dogsledder. Unfortunately, circumstantial evidence suggests that this fella is his father, for various reasons, including a shortage of plausible choices and a mutual liking for blue cheese. And it turns out to be true.

** Also averted with Rachel's unplanned pregnancy when [[spoiler:the dad is Ross, her one true love, and not the random way too young dude she just broke up with]].
* Done three times with the same pregnancy on {{Neighbours}}. Bear with me: first Sky was with Dylan, but cheated on him with her art teacher, breaking them up. A few weeks later, Sky has a one night stand with Dylan's brother Stingray, who is also her best friend. Shortly afterwards, she discovers she is pregnant. When Stingray asks if it could be his baby, she says that she wishes he was, but the dates don't add up. As soon as Dylan has accepted he is the father and become excited, a scan shows that the baby is younger than originally thought, making Stingray the father. This destroys the relationships of Dylan and Sky, Stingray and Rachel, and Dylan and Stingray. Then when the baby is born, a DNA test shows Dylan is the father after all- but Sky's relationship with Dylan is over permanently, and she ends up with Stingray.

* On ''{{Lost}}'', Sun is worried that the father of her child is the man she had an affair with, rather than her husband Jin's. Juliet helps her confirm the date of conception. [[spoiler:[[SubvertedTrope It's Jin's]].]]

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* On ''{{Lost}}'', Sun is worried that the father of her child is the man she had an affair with, rather than her husband Jin's. Juliet helps her confirm the date of conception. [[spoiler:[[SubvertedTropeIt's Jin's]].]]

* Exception: On ''{{Lost}}'', Sun is worried that the father of her child is the man she had an affair with, rather than her husband Jin's. Juliet helps her confirm the date of conception. [[spoiler:It's Jin's.]]

* Played with in ''SomethingPositive:'' [[JerkWithAHeartOfGold Davan]] ''doesn't'' want to be Rory's biological father, but while he's willing to step up, the other (unnamed, unseen) guy isn't. Even when Davan is cleared by a DNA test, he becomes Rory's ParentalSubstitute anyway.

* Brazilian SoapOpera ''Por Amor'': the main "villainess" raised her two sons very differently because she believed that her favorite one was the one she bore with the man she was and still is truly in love with... who, incidentally, [[YourCheatingHeart isn't her husband of 30 years]]. All the men involved learn about it, DNA tests ensue, and it's revealed that the biological son of her true love was TheUnfavorite. Cue her being abandoned by her family and her ex-lover, and a VillanousBSOD.

This may lead to a WallBanger. But it can be done well, and it is OlderThanDirt.