History Main / LawOfInversePaternity

->''"The odds that a given character is the biological father of someone whose paternity is unknown is directly inverse to how badly the other parties directly concerned want him to be the biological father."''

Or, to put it in plainer terms: ''If it is strongly hoped that a given character is the biological father of a character of unknown paternity, he probably won't be. If it is strongly hoped that a given character'' '''''isn't''''' ''the biological father of a character of unknown paternity, he even more probably will be.''

A Sub-trope of WhosYourDaddy, although it may also be coupled with LawOfInverseFertility if it comes into play early enough. Owes its existence to the RuleOfDrama, much like many other tropes.

[[folder:Film]]
* In ''Film/SnowDogs'' (starring Creator/CubaGoodingJr), the protagonist goes to Alaska to find his real father. He develops mutual hatred 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.

* ''Series/{{Friends}}'':
** Subverted when Chandler and Monica find out their adopted children could have been fathered either by a smart scholarship student, or by a man who killed his father with a shovel. Chandler thinks this trope will come into play, given they're already victims of the LawOfInverseFertility. However, it's {{Subverted|Trope}} and Chandler is wrong. Turns out that the sex act the girl and the killer did couldn't cause pregnancy.

** Zig-zagged with Rachel's unplanned pregnancy -- on the one hand, [[spoiler:the dad is Ross, her one true love, and not her slightly younger ex-boyfriend]], but on the other hand, [[spoiler:it was a one-night-stand with Ross, as opposed to the presumably regular sexual activity she was having with her steady boyfriend. AND she and Ross used a condom]].

[[folder:Anime & Manga]
* In ''Manga/{{Nana}}'', after [[spoiler: starting a 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.

* This came into play in ''Film/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.

* In Creator/JulietMarillier's ''Son of the Shadows'', Eamonn tries to pull this, telling Bran (who has trust issues) that Liadan's son might be his. However as the audience knows, Liadan never had sex with Eamonn, and by this point Bran is learning to trust more, and Eamonn's ploy does not work.

* ''{{Series/Casualty}}'': [[spoiler:Played straight with Selena realizing that Nathan was the biological father of her baby, not Harry]]. In its SpinOff, ''Series/HolbyCity,'' the Williams family history has become particularly contorted by the result of a paternity test; it was revealed that Chrissie was conceived by the rape of her mother by her presumed father's father, making her presumed father her actual half-brother.
* ''Series/UglyBetty'':
** A variation--[[spoiler:Henry finds out that he was the father of Charlie's baby.]]
** Done again when Hilda ends up pregnant with Bobby's child, who her family disapprove of, instead of Archie's, who is she is dating.
* Brazilian SoapOpera ''Series/PorAmor'': 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, 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.

** And on ''Series/GeneralHospital'', when Brenda slept with husband Jax and ex-lover Sonny. . .only to not get pregnant at all.

* Done three times with the same pregnancy on ''Series/{{Neighbours}}''. Bear with us: 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 earlier, which later causes Kerry to develop cancer--but Sky's relationship with Dylan is over permanently, and she ends up with Stingray.

* Subverted in the Creator/DavidTennant four-part drama ''Single Father''. The main character Dave lives with his three kids and his partner's daughter from an earlier (and extremely brief) relationship. Suspicions arise that the other three kids were ''also'' fathered by the same man as the daughter, so Dave goes for a paternity test and it's obvious that the writers are setting this trope up... But no, turns out they're his after all.
* Subverted on ''Series/{{Community}}'', when Shirley's baby turns out to be [[spoiler: her ex-husband's rather than her one-night-stand Chang's.]]
* PlayedWith on ''Series/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.
* On ''Series/MyNameIsEarl'', Joy has an affair with Darnell while she's still married to Earl, after the stress of taking care of a colicky Dodge took a toll on the marriage. Several months into the affair, she finds out she's pregnant and excitedly shows Earl the positive test. Then she has an OhCrap moment as she realizes that there's a good chance the baby ''isn't'' Earl's... and that there's a good chance of delivering a ChocolateBaby. She even asks the doctor who's giving her an ultrasound to see if he can tell the baby's race. In keeping with this trope, she gives birth to a black baby... and Earl ''almost'' leaves her. [[spoiler: It turns out that Earl Jr. might not be Darnell's, either based on a DaddyDNATest,]] but [[CutShort that plot point was unresolved]] thanks to the 2007 UsefulNotes/TVStrikes.
* The talk show ''Series/{{Maury}}'' lives on this trope. The most frequent episode format involves a woman seeking a paternity test for her child... often with a man (or multiple men) she hates so that she can spitefully hit him up for child support. The more tearjerking variant involves married couples where the husband is heartbroken to learn that his beloved child isn't biologically his due to his wife's affair.

* ''Series/{{Poldark}}'': It would be better for pretty much every character if [[spoiler:Elizabeth's baby in Series 3 were her new husband George's]]. [[RuleOfDrama Naturally,]] it's [[spoiler:Ross's, and the result of a one-night affair.]]

* ''Manhwa/TheRemarriedEmpress'': It's revealed [[spoiler:that it was Sovieshu who was left infertile by a childhood incident and not Navier as he initially believed. Which means he isn't the father of Rashta's baby as he was hoping to secure a needed heir, rending the whole reason he divorced Navier to marry Rashta AllForNothing.]]

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 Charles, the hypotenuse--her worst nightmare. The law applies to the men too: Bob will hope he's the father before anyone knows for sure and be disappointed when the truth is known, while Charles will have much stronger misgivings than Bob (often treated sympathetically) about taking on the responsibilities of fatherhood.

[[folder: Anime & Manga ]]

[[folder: Film ]]

[[folder: Literature ]]

* In Juliet Marillier's ''Son of the Shadows'', Eamonn tries to pull this, telling Bran (who has trust issues) that Liadan's son might be his. However as the audience knows, Liadan never had sex with Eamonn, and by this point Bran is learning to trust more, and Eamonn's ploy does not work.

[[folder: Live Action TV ]]

[[folder: Theatre ]]

* OlderThanFeudalism: This happened in ''Theatre/OedipusTheKing'' after Oedipus learned that he was adopted.

[[folder: Webcomics ]]

[[folder: Western Animation ]]

* ''Webcomic/TheRemarriedEmpress'': It's revealed [[spoiler:that it was Sovieshu who was left infertile by a childhood incident and not Navier as he initially believed. Which means he isn't the father of Rashta's baby as he was hoping to secure a needed heir, rending the whole reason he divorced Navier to marry Rashta AllForNothing.]]

* Brazilian SoapOpera ''Series/PorAmor'': 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.

* ''{{Series/Casualty}}'': [[spoiler:played straight with Selena realizing that Nathan was the biological father of her baby, not Harry]].
** In its SpinOff, ''Series/HolbyCity,'' the Williams family history has become particularly contorted by the result of a paternity test; it was revealed that Chrissie was conceived by the rape of her mother by her presumed father's father, making her presumed father her actual half brother.
* ''Series/UglyBetty'': A variation--[[spoiler:Henry finds out that he was father of Charlie's baby.]]

* Brazilian SoapOpera ''Series/PorAmor'': 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.

* Subverted in ''{{WesternAnimation/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.

* On ''Series/{{Supernatural}}'', Dean has his girlfriend Lisa and her son Ben. Ben is about the right age to be conceived from a previous fling between Dean and Lisa, and he wishes he were the father, but Lisa makes it clear that he isn't. She's never said anything about who Ben's father is; she probably doesn't think it's any of his business, or, as a demon once accused, she may have been promiscuous enough at that time that she has no idea who the father is (in which case, maybe it really is Dean).

* Done three times with the same pregnancy on ''Series/{{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 earlier, which later causes Kerry to develop cancer--but Sky's relationship with Dylan is over permanently, and she ends up with Stingray.

* In Juliet Marillier's Son of the Shadows, Eamonn tries to pull this, telling Bran (who has trust issues) that Liadan's son might be his. However as the audience knows, Liadan never had sex with Eamonn, and by this point Bran is learning to trust more, and Eamonn's ploy does not work.

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

* On ''Series/{{Supernatural}}'', Dean has his girlfriend Lisa and her son Ben. Ben is about the right age to be conceived from a previous fling between Dean and Lisa, and he probably wishes he were the father, but Lisa makes it clear that he isn't. She's never said anything about who Ben's father is; she probably doesn't think it's any of his business, or, as a demon once accused, she may have been promiscuous enough at that time that she has no idea who the father is (in which case, maybe it really is Dean).
* ''Series/{{Poldark}}'': It would be better for pretty much every character if [[spoiler:Elizabeth's baby in Series 3 was her new husband George's]]. [[RuleOfDrama Naturally,]] it's [[spoiler:Ross's, and the result of a one-night affair.]]