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Daddy DNA Test

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It is discovered that a character, or a baby, has a parent whose identity is not known. Solution? Get a DNA test. Prove beyond a reasonable doubt who the father really is, and proceed from there. All the other guys who aren't the dad can go home. (Well, unless the real daddy is a Glorified Sperm Donor and the fake one has actually been there for the kid their whole life. In which case, go take a hike sperm daddy.)

The only case in which this would not help is if two or more identical siblings or clones are potential fathers to the child; having the same DNA, all of them will test positive for paternity if any of them does.

This trope can also occur with mothers, but that's a much rarer occurrence (barring a babynapping, a switcheroo with a different newborn, or a delivery while the woman is unconscious, the mother knows the baby she just birthed is her own). This test can also be used indirectly to link siblings together. In any case, how long it takes for the DNA test to get finished typically depends on the speed of the plot. The DNA test could present complications: if the bad guys know about the test, they may attempt to keep the Status Quo by altering the test results (of course, they must force other characters into secrecy about that, and in any case it won't last for long).

Works made prior to the invention of DNA testing may have a more primitive version of this in the form of blood tests for paternity, which could eliminate candidates under certain conditions. For example, if a type O mom had a type A baby, then a type B man cannot be the father. See a full listing of impossible blood type combinations here.

May result in a Surprise Incest, if the character was in a relationship with someone who turned out to be a relation.

Almost always happens at some point after a Luke, I Might Be Your Father revelation. Also happens if a woman decides to have My Secret Pregnancy. The Trope Breaker for Mama's Baby, Papa's Maybe. Also see Gene Hunting.


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    Anime & Manga 
  • Very irritatingly avoided in Please Twins!. They explain that it "costs too much money" …the episode before they win a lot of money and blow it on a Hot Springs Episode.
  • In Mobile Suit Gundam Wing: Endless Waltz, Mariemaia claims that Treize being her father has been confirmed through DNA testing. We never actually see the results of the test though, and there is considerable doubt on Mariemaia's parentage all the same. She is later adopted by Lady Une, who was Treize's then-current girlfriend in the series proper, until Wufei killed him in the final episode.
  • Naruto Gaiden does a Mommy DNA Test, when Sasuke's daughter, Sarada, begins to suspect that her father's former teammate, Karin, may be her real mother. The DNA test comes out positive, seemingly confirming this. But it later turns out that the test was positive because the umbilical cord used as a sample for it was actually Sarada's, not Karin's, so Sakura was Sarada's biological mother all along.

    Comic Books 
  • Batman: In a story arc in Batman: Gotham Knights had the villain Bane discovering evidence suggesting that his real father was an American doctor, and, as the doctor has died, seeking a DNA matching test with the doctor's son — Bruce Wayne.
  • Spider-Man: In Sins Past, Peter knows he's not the father of twins Gabriel and Sarah Stacy but tests his blood sample with the twin's blood sample to find out for sure. Justified, since he and Gwen haven't even slept together prior to the twin's conception and this leads to him discovering that Gwen cheated on him and Mary Jane confirming his worst.
  • Superman: A variation in H'el on Earth When Superman puts his battle-suit on Superboy, the family crest should have changed the instant it identified his Kryptonian bloodline. It stayed the same, confirming Superman's suspicions that Superboy's his clone.

    Fan Works 
  • In the final chapter of MGLN Crisis, Fate takes a DNA test and it's revealed that her father is her adoptive mother's late husband, Clyde Harlaown. Though the truth turns out to be slightly more complicated when she does further investigation in the sequel.
  • In Unexpected Surprise, Gabriel sees Marinette with a young daughter looking exactly like his long dead wife, so he secretly runs a DNA test to check if the girl might be Adrien's daughter. When he finds that she is, he rewrites his will accordingly.
  • In Take a Stand Nick Wilde takes a paternity test after Luna, the six-year old daughter of one of his ex-girlfriends, calls him "daddy". It's positive.
  • In Give In, Give In [and Relish Every Minute of It], Frollo finds out he fathered a son from a one night stand fifteen years ago. His son, Quasimodo, comes to live with him after his mother and step-father are killed. To make sure that Quasimodo is his son, Frollo does a DNA test.
  • When Severus Snape needs an emergency blood transfusion in The Peace Not Promised, his father reveals that he had Severus tested years ago to ensure that he's actually his son, so he knows that they're compatible.
  • Ruby and Yang learn in Who Needs Genetics When We Have Family? that their father Taiyang was in a relationship with both their mother Summer and uncle Qrow. However, it's unclear which sired Ruby, because Ruby only takes after Summer. Ruby's parents decided to wait until adulthood to get a DNA test. Depending on who's Ruby's biological father, Ruby and Yang are half-sisters or cousins. The story ends not revealing the results to the reader.
  • In chapter 60 of the Fairy Tail fic To Become a Father, an annonymous DNA test confirms that Cana Alberona is Gildarts Clive's daughter... and reveals that she's at risk for a life-threatening disease that had killed her mother. Gildarts ended up learning about both the paternity test result and potential disease risk and begins searching for his missing, ill child.
    • In the lighter spin-off DNA, a similar DNA test confirms that Erza Scarlet is related to the late, 400-years-old Queen Irene Beleserion base on DNA from an archeology site. Or more accurately, that she is her several times tested and confirmed blood daughter.

    Films — Animation 
  • In Ratatouille to see if Linguini is Gusteau's son. The testing hit a slight snag when the first sample was identified as "rodent".

    Films — Live-Action 
  • Done in Elf to confirm that Buddy is Walter's son.
  • The So Bad, It's Good movie Une chance sur deux (Half a Chance): Alice gets a DNA test to find out who her real father is but she likes the two possible dads so much that she throws away the results.
  • Baby Mama actually has the inverse with a court ordered maternity test. The premise of the movie was that a surrogate mother is artificially impregnated using the other woman's egg and her own husband's sperm. The test is because she has the child rather late after the egg was inserted and it's unclear who the biological mother is. It turns out to be the surrogate mother's, but it's okay, because she gets pregnant herself by her new boyfriend.
  • A variation on an Ancient Chinese proto-blood test has been employed to prove the parentage of a baby in a variety of period dramas set in the old days in several Chinese films. In at least one of these, an imposter was promptly sentenced to death when it was proven the son was not theirs.
  • In White Frog, Oliver once had his younger son Nick take one, since Nick doesn't look much like either of his parents, and nobody else in the family has his "problem." Nick really is his, but his wife Irene found out about the test and was angry and hurt.
  • In Relative Fear, Linda has Adam take one to confirm her suspicions that he was Switched at Birth.

  • Plays an important role in the Adrian Mole series, where a DNA test reveals that Adrian is the father of Glenn Bott, and later that his sister Rosie is the daughter of their mother's ex-lover Mr Lucas.
  • The Tales of Kolmar series takes place in a medieval world, but it's apparently possible for a demon to confirm who someone's father is.
  • In Maeve Binchy's Minding Frankie, the hero tests if he really is the father of the eponymous Frankie. He finds out he is not, then decides the DNA result does not matter, he is her father in every way that matters.
  • In Malorie Blackman's book Boys Dont Cry, Dante takes one of these tests to check that he is really the father of baby Emma, when his ex-girlfriend dumps her at his house. He decides that he'll have to give up his place at college to look after her before the results arrive, even if she isn't his daughter. She is.
  • There's More Than One Way Home: Anna spends two years believing that Alex has had a vasectomy, meaning Marissa's father is Val. When she learns that in fact he was fertile the entire time, she suggests a DNA test, but Alex doesn't care about Marissa's paternity.
  • The Inheritance Games:
    • When Tobias Hawthorne leaves his fortune to Avery Grambs (who he seemingly has no connection to) instead of any of his (grand)children, people start speculating that she is his secret illegitimate child. A DNA test proves Avery is not a Hawthorne. However, when it turns out Tobias' son Toby was adopted, Avery starts thinking that he may be her father, since it turns out that he had an affair with Avery's mother. He's not. A paternity proves that Ricky Grambs is her father after all.
    • After Skye gave birth to Xander, Isaiah Alexander realized the child was probably his and sued for custody. Tobias Hawthorne faked a negative paternity to make sure he lost the lawsuit, so that he could raise his grandson himself.

    Live-Action TV 
  • Used to establish that Christian is the father of Matt in Nip/Tuck.
  • House:
    • House gets a DNA test after his father's funeral, proving that they're not related. Given that they had an extremely tempestuous relationship House is relieved to find this out. Amusingly enough, the man House presumed to be his biological father also wasn't. Meaning his mother had at least one more affair.
    • One episode revolves around House going to great lengths to prove that his patient's father is not the real father and gets both the parents tested. Turns out both aren't his biological parents and he's adopted.
    • House also performs a paternity test on one of his "friends" and his current patient, who told him she's his estranged daughter from an old fling. House tells the kid that his friend is her father, but the test result House gets later on turns out to be negative.
    • Another episode has House trying to prove that at least one of Taub's kids isn't his. Eventually Taub gets the results, but shreds them without looking.
  • Veronica Mars
    • The titular heroine suspects at one point that her real father is her ex-boyfriend Duncan's dad, so she runs a paternity test, which she shreds without reading, deciding she doesn't need to know. Later in the season, Keith Mars has his own test done, which confirms that he is, after all, her real father. This is also why Duncan doesn't talk about the night he and Veronica (who was drunk and roofied at the time) had sex for the first time. He assumes it's because both of them are ashamed of Brother–Sister Incest. In fact, Veronica simply doesn't remember.
    • Also done, though not with a DNA test, with Trina Echols, who was adopted. Trina claimed publicly that she needed a bone marrow transplant to smoke out her real parents. Her mother came forward. Her father was a Jerkass.
  • Dorothy and her mom from The Golden Girls.
  • Sidney and Jack Bristow from Alias had to go through this due to speculation that Sidney's biological father was actually Sloane. Turns out Jack is her real father.
  • In My Two Dads, the dads throw away the results, but they needed a little persuading.
  • Often featured on sleazy daytime shows like The Jerry Springer Show, where it's used to determine whether a woman was cheating on her boyfriend/husband with another man or to prove that a man is the father of a child when he denies it.
  • These days every other episode of Maury. In one amusing example, a young mother brought no fewer than a half dozen possible fathers onto the show for testing. After a long drawn-out process of discussing her lifestyle and her complicated parenting situation, the results come back and… none of them are the father! Like a pack of hounds, all the tested would-be fathers round shouting at the girl. "There's even more?!"
  • These days at least once an episode on The Jeremy Kyle Show.
  • The best known feature of the Point-and-Laugh Show of Brazilian host Carlos Massa, aka Ratinho. There is even a song played after the result, one particularly memetic ("[he is not the dad\but he is the dad], his wife complained but he [is\is not] the dad!").
  • Ugly Betty:
    • Amanda Tanen attempts this on Bradford Meade when she suspects him of being her real father. He isn't. Which is a relief to Amanda, since otherwise she and Daniel Meade would have committed Surprise Incest.
    • Daniel Meade receives a letter telling him he is the father of Daniel Jr., the child of a French model he met years ago on a business trip. The paternity test reveals that Daniel Jr.'s "father" is Alexis Meade, Daniel's transgender sister.
  • In the Monk episode "Mr. Monk Gets a New Shrink," Dr. Kroger is revealed to have a stormy relationship with his son Troy. Namely, because Troy has made him take three paternity tests because he didn't believe they were related. Also, Randy has arrested Troy on at least one or two previous occasions.
  • It's Always Sunny in Philadelphia averts this—Charlie is, more likely than not, Frank's son, but Frank refuses to have the DNA test.
  • A staple of soap operas. Count on someone to conceal and/or falsify the results.
  • Lois & Clark: In "Chip Off The Old Clark", this was used when a little boy displayed Kryptonian powers. The boy's mother claimed that Superman was the father, while a shocked Superman protests that he's never seen her before, let alone slept with her. One guy claimed the test wasn't needed, as it must be obvious that Superman is the father. The boy was human, and the super powers had been transferred to him.
  • In My Name Is Earl, Earl has Dodge and Earl Jr.'s DNA tested to find out who Dodge's real father is. It turns out it was him all the time. Earl and Joy conceived Dodge at a Halloween party. It's also revealed that Earl Jr.'s real father is not Darnell as was previously thought. It's never revealed who his father actually is. Word of God says Earl Jr.'s father was supposed to be someone famous, but due to the series' cancellation, they never got to do that plotline.
  • In an episode of Smallville a woman appears who thinks Clark is her son and demands a DNA test. Clark gets his Secret-Keeper Pete to donate a DNA sample after breaking into the lab, so the results won't reveal that Clark isn't human.
    Pete: Man, this "Mission Impossible" stuff is great. But other than my scintillating conversational skills, I still don't understand why you brought me along.
    Clark I need your spit.
  • Dexter has a DNA test done to confirm that the man whose house he inherited was really his birth father.
  • Done confusingly on Gossip Girl in season three with Elizabeth who claims to be Chuck's (supposedly dead) birth mother. Chuck gets a DNA test which proves that she is his mother, but it's implied that the results were tampered with by his Uncle Jack. As of season four we still haven't found out for sure whether or not Elizabeth is his mother.
  • Parodied on Dinosaurs: Due to a mix-up, it's suggested that the Sinclairs accidentally got another family's egg (the one that hatched into Baby) while the other family, who look more like Baby, got theirs, which looks more like the Sinclairs. Earl and the other father are subjected to battery after battery of bizarre tests (including a centrifuge)... and then the doctor just takes the blood test anyway. The test said the eggs were switched but it was later revealed it was a mistake.
  • CSI
    • Warrick got one just before his death, as part of his attempt to gain custody of his infant son. His colleagues only discover this when they find the test results while retrieving clothes to bury him in.
    • Catherine inverted it. She ran her DNA against Sam Braun’s when she began to suspect he was her father, and it proved he was.
  • High-tech alien version occurs in the series finale of Farscape. The fact that Aeryn needs to find out who her baby's daddy is forms a major theme of the final series.
    • Earlier, Aeryn is convinced that an alien is her long-lost father via high-tech DNA test. The test results were actually faked.
  • Boston Legal: A man who was born out of artificial insemination was dating a woman who was born the same way and they were afraid of being half-siblings. To learn if they had the same father or not, they sued the lab to force them to tell because a DNA test using only the couple's blood would be inconclusive if they were half-siblings or complete strangers. (Whether this counts as a case of the writers failing to do the research or just "Because The Plot Demanded It", it's still scientifically incorrect: Half-siblings should be a roughly 25% genetic match, and as such, fairly easy for a DNA test to catch, particularly if they have DNA from either of their mothers.)
  • On NCIS, Abby tests her DNA against the DNA of the woman that she thought was her mother and finds out that she's adopted.
  • Drives the plot of the Firefly episode "Heart of Gold." At the titular bordello, a local petty tyrant forcibly takes a DNA sample from the unborn child of one of the prostitutes, promising to return for the child if it's his (and it is, of course). The madame hires the crew of Serenity to help drive him off.
  • In Gilmore Girls, April shows up at Luke's one day, tells him that she's the daughter of his old girlfriend, and asks for a DNA sample. The unique part is that she only wants to do the test as a science project. The bigger implications of identifying her father seem lost on her at that point.
  • On The Red Green Show, an old rich guy dies, and since he amassed his fortune by donating to the local sperm bank, everyone in town gets DNA tested hoping to get a match, and therefore be entitled to the inheritance. Shockingly, all of the DNA tests turn out to be exactly the same. Incestuous implications aside, this unfortunately only entitles everyone to a few bucks each since the inheritance has to be split so many ways. It turns out that this was because Mike stole all the test tubes, so the testers had to use the lids off pickle jars, and simply ended up testing the chemical composition of pickle juice. The reason this matched the old guy's DNA was because he was always pickled himself.
  • In the later half of Season 1 of Shameless (US), Monica does one of these to prove that Liam, long believed to be from a fling from a black man, isn't Frank's son. Turns out he really is Frank's son. Of course it then gets revealed that Ian isn't Frank's son but one of his uncle's sons.
  • Moonlight: Mick finds out that he might have a son with a friend's wife he slept with while they both thought his friend was dead. It seems likely at first, given that the baby was born seven months after his friend got back. Mick snabs a sample of the guy's hair and some DNA of his own from his human days for a test. It shows that Mick isn't his father, and the son was just premature.
  • On Chicago P.D. Lindsay has always thought she knew who her dad was, even if he was a deadbeat who was never part of her life. After Jimmy suddenly shows up one day, Lindsay's suspicious boyfriend has a DNA test done. Jimmy isn't Lindsay's biological father.
  • Happens from time to time in Star Trek. The guest star of the week may be some kid who was orphaned or captured, and the crew needs to find his closest living relatives - apparently most spacefaring civilizations keep a genetic database of all their citizens. Other times, someone will show up claiming to be related to one of the main cast and uses a genetic test to validate the claim.
  • In an episode of Malcolm in the Middle, Lois discovers that her father, Victor, had a secret family with a woman named Sylvia (played by Betty White), and Ida, Lois' mother, was planning to sue her for Victor's tiny pension, despite the result being financial ruin even if she won. Lois tried to talk to Sylvia to hand over the pension, so that Ida would have one final memory of her late husband and leave her alone, but Sylvia refuses out spite for Ida. Lois decides to back up Ida's lawsuit, and as they're preparing the evidence and court documentation, Lois gets the DNA test the lawyer advised her to take, and is shocked to discover that Victor is not her biological father, and Ida theorizes that the most likely candidate was a guy from the old country who could walk upstairs on his hands, and admits that Susan, Lois' sister, may have been fathered by another man as well.
  • The Republic of Sarah: Corinne gets a paternity test done for Josh, her son, as she's unsure whether Danny or Adam is his father. Sarah tells Corinne that Adam is the father, but this turns out to be a lie; Danny was the father, but Sarah lied in the hopes that Corinne would end her relationship with Danny.
  • The Keith and Paddy Picture Show plays this for laughs when the pair recreate Return of the Jedi. When Luke asks Yoda if Darth Vader is really his father, Yoda prompts Luke to ask Jeremy Kyle, who has just got the DNA test results, which confirm Vader as Luke’s father. Luke proceeds to realise the Surprise Incest between him and Leia, which prompts an argument with Yoda, to which Kyle declares an ad break, giving commentary like that on his own show.

    Newspaper Comics 
  • Interesting twist in Safe Havens: Samantha runs a genetic profile on her daughter Maria. She has no doubts at all about Maria's parentage, but she is a geneticist by profession so naturally she's curious about what's in her daughter's DNA. However, she keeps getting Maria's profile mixed up with the other Maria's- Maria the time traveler- because they're identical...and she freezes as the implications sink in.
    Maria: Hi Mom.

    Pro Wrestling 
  • Paul Bearer subjected himself to this to prove to the world that he’s Kane’s biological father from an affair he had with The Undertaker’s mother. The test shows that Paul Bearer is indeed Kane’s father.

    Video Games 
  • In Metal Gear Solid V: The Phantom Pain Miller and Ocelot suspect Eli is one of Big Boss's clones and compare he DNA to Snake's to verify this. The results come back negative, leading them to conclude that the resemblance is simply a coincidence. Given that Eli is very obviously a young Liquid Snake this information only serves to clue-in fans that something isn't right. As it turns out Eli is indeed Liquid. The reason the DNA test didn't find a match is that Snake isn't Big Boss

    Web Animation 
  • Etra chan saw it!:
    • Yuzuriha insists Kuroki have a DNA test with his son to satisfy her suspicion about the boy's parentage. When the test reveals that Kuroki's son is not related to him, she faints.
    • Akamatsu forces Karin to take a DNA test out of an allegation of cheating. Unsurprisingly, the baby was Akamatsu's, but Karin still divorces him because of his stupidity and distrust.
    • After Akane gave birth to her child, Hiiragi insists that the baby was his until his father requests a DNA test since there is a chance that the child is Kuroki's, who was Akane's previous husband. Hilariously, neither of the men is the child's father, but instead, it's Akamatsu.
    • When Tachibana hears a rumor that Azami isn't his daughter, he does a DNA test on her and gets a zero percent match. It turns out that Akane cheated on him with Hiiragi.
    • Hiiragi requests a DNA test for his and Yuri's baby and asks his family to submit their DNA as well for a more accurate result. It turns out the test wasn't for his and Yuri's baby, but to confirm whether or not Kuroki is his real father. The test reveals a zero percent match, exposing Akane's affair.
    • Azami claims to be Tachibana's illegitimate daughter, however, Karin demands a DNA test to confirm her paternity. The result reveals that Azami is not Tachibana's daughter, and she actually turns out to be Hiiragi's illegitimate daughter from his affair with another woman. It is revealed that Hiiragi actually tried to pin the blame on Tachibana for his affair by using his daughter to cover his tracks.
    • Karin decides to get a DNA test when a senile Akamatsu claimed that he was her father, instead of Tachibana. When the results came out, Katsura turns out to be Tachibana's only child, while Hiiragi turns out to be the product of Akane's affair with another man, and Karin turns out to be not biologically related to either of them because she was accidentally switched with another baby at birth.
  • Otakebi: Bob's father secretly did a DNA test on his sons after he became suspicious of his wife's affair, Bob is revealed to be his only biological son.
  • Revenge Films:
    • "I asked my wife to go on a date. She was surprised to see the man she was cheating on with": After divorcing his wife Emily and banishing her to her lover Kevin's apartment, on top of finding out she did it with Kevin while pregnant, he realized a DNA test on their 1-year-old son Jonathan and found out the baby was Kevin's all along.
    • "Found out my son wasn't related to me…": The OP realized a DNA test on his son on his fourth birthday when his brother told him the boy had a different and unlikely blood type from his own. When the test results confirmed it, he fell into depression and even tried to take his own life. To make matters worse, the cheating wife's lover wasn't even the real father; his wife had many different lovers.

    Web Comics 
  • Batman and Sons mentions that Bruce is taking care of baby Terry, but not baby Damian, because Catwoman thought to do a DNA test before handing over her kid, whereas Talia keeps Damian to herself and just keeps sending him bills.
  • In Something*Positive, Davan has Sex for Solace with the ex-girlfriend of his friend who recently committed suicide. Years later, the two meet up again and Davan finds out she had a son named Rory, whose father is either Davan or the man she dated shortly after their tryst. The test shows that Davan isn't the father, but Law of Inverse Paternity kicks in and he becomes Rory's Parental Substitute anyway.
  • One arc of Casey and Andy had Jen meet her Kid from the Future, who accidentally left a strand of her hair behind. She takes it to the titular Mad Scientist duo to have them determine who she would have the kid with. The test confirms that the father is her Love Interest Quantum Cop, though a quick shot from the last panel of the arc teased the (ultimately unused) possibility that the father might have been his evil alternate dimension counterpart, Quantum Crook.

    Web Original 

    Western Animation 
  • When Homer on The Simpsons wanted to know if his dad was Abe or a lifeguard named Mason Fairbanks. He wasn't, but Abe switched the labels because Homer seemed too interested in Fairbanks.
  • In The Boondocks episode "The Story of Lando Freeman", Robert Freeman goes on The Steve Wilkos Show, where a DNA test reveals that the titular Lando is his long-lost son... but this is subverted by the reveal that they lied about the test results on camera, only putting a disclaimer in the credits. Lando's real father is Billy Dee Williams.
  • On Gargoyles, Dr. Sevarius does a DNA test on Angela (against her will) and happens to discover that Goliath is her biological father. This shocks her and winds up causing some drama, since Goliath follows the gargoyle tradition where biological relationships aren't important.
  • On South Park, Eric Cartman had no idea who his father was. Neither did his mother considering the number of possible candidates so a blood test was taken. It was then revealed his father was his "mother", who was actually a hermaphrodite who had a penis (much to the disgust of the men who only learned when Dr. Mephisto brought it up) and impregnated some woman. Cartman briefly asked who his real mother was, much to the horror of the men who believed they could have been his Dad, but, once Ms. Crabtree the school bus driver, Principal Victoria and the Mayor of South Park were introduced as options, Cartman decided he didn't want to know. Of course many many seasons later it was revealed that the whole thing was a ruse, Cartman's mother is actually biologically female, and Cartman's father is Scott Tenorman's father, who Cartman had killed and tricked Scott into eating in a bowl of chili. The reason they hid the truth was because Tenorman was a member of the Denver Broncos and the townspeople didn't want to ruin the team's good season by distracting them with an illegitimate child scandal.
  • On Futurama, Kif's Bizarre Alien Biology means that when he's "receptive" he can be impregnated by anyone he makes skin-to-skin contact with. Necessitating the use of the Professor's "maternifuge" to determine who the DNA donor was. It was Leela, but by Kif's cultural norms his girlfriend Amy is still considered the "mother" as she triggered his receptive phase, the only reason they bothered with the test was to make sure it wasn't Zapp Brannigan.
  • On BoJack Horseman, 18-year-old Hollyhock claims to be Bojack's long-lost daughter, and they are a DNA match. This trope ends up being subverted in the end of the season when it's revealed that she's his sister, not his daughter, resulting from an affair his father had with the maid.
  • Justice League: In "Epilogue", the elderly Bruce Wayne needs a new kidney. Terry McGinnis checks himself for compatibility, and finds that he's a perfect match. Suspicious, Terry has a test done and discovers he is Bruce's biological son, which drives the rest of the episode.
  • Archer: In season 2's "Blood Test" Archer is forced to take a paternity test by a prostitute who claims her infant son is his. Malory, who doesn't want the shame of a bastard grandchild, forces Archer to swap his blood sample for one from Cyril Figgis. The test yields a positive result anyway because it turns out Cyril is the actual biological father. Archer still gets stuck paying child support as he can't prove the sample was switched.

    Real Life 
  • A regular (usually weekly) occurrence at family courts around the world. It's usually not usually that dramatic; the results are less "You are the father!" and more "DNA testing ordered by this court on June 17, 2016 and conducted June 30, 2016 shows a 99.5% probability that the defendant is the father of the child. The court is therefore satisfied of defendant's paternity of the child and enters an order of paternity. Child support is set at $65 per week with $18 per week arrears payable through Probation. . . ."
  • The paternity of Anna Nicole Smith's daughter, Dannielynn, was a tabloid sensation during late 2006 and early 2007, with Smith's boyfriend and several other alleged lovers claiming paternity. A paternity test revealed a former lover as the father.
  • Patty Duke had several lovers over the years, and a test was eventually done to determine the true father of her son Sean Astin. His father is Michael Tell, but her other lovers Desi Arnaz Jr., John Astin (who officially adopted him), and Michael Pierce all helped raise him.
  • Not DNA, but Ward's Science markets a prepackaged blood-typing simulation kit that's specifically designed so that it can be staged as this trope for a lesson. Three of the four simulated-blood samples to be tested are labeled with men's names, while the fourth is "Ms. Brown". As "Ms. Brown" tests as O- and the "men" all have different ABO blood types, lab instructors can tell students that they need to determine which of the guys in Ms. Brown's life could have fathered her B+ baby, confident that they'll narrow it down to one option.