A woman finds out she is pregnant, and is uncertain which of her lovers (often a husband and a boyfriend) is the father of the baby.
This may resolve a number of ways:
- The mother, upon learning the child's paternity, hides it so that her current partner will not leave her. (Or alternatively, so that the biological father will be safe from negative consequences.)
- The mother's new partner, discovering the baby is not his, abandons her, leaves her to cope with raising the child on her own. If the child is already old enough to remember this, this can be a pivotal traumatic childhood event.
- The mother's husband raises the child out of a sense of duty, but always resents the child and puts his biological children first.
- The mother's new partner demonstrates what a good person he is by vowing to love and raise the child as his own.
- The biological father, upon discovering his child's paternity, vows to love and raise the child.
- The truth is never revealed, leaving everyone uncertain.
See also Gene Hunting, in which the child seeks his or her parentage. Nothing to do with the stock phrase used when one person taunts another in a fight. Also to not be confused with the video game of the same name.
- The Big Bad of Part 5 of Jojos Bizarre Adventure is an inversion. His mother was an inmate at an all female prison with all female guards, and she'd already been there for two years when she gave birth. Not only that, but the pregnancy itself was unusually long. There are basically no possible paternity candidates at all.
- Hachi's first pregnancy in Nana. It remains unclear which of two possible men fathered her son.
- The issue of paternity shows up in The Smurfs story "The Baby Smurf", despite the fact that the child came by Delivery Stork.
- Played with in Spider-Girl, when a "new" Spider-Man shows up. After lots of hints that he's Peter's illegitimate son with ex-girlfriend Felicia Hardy, it turns out he's really the son of the first Spider-Woman, Jessica Drew.
- Spider-Woman: Jessica Drew has yet to reveal who the father of her newborn son is; the only certainty is that it isn't Tony Stark (he was the only one who asked, and her reply was to dump a plate of food on him; clearly she has a reason to keep it secret). It's revealed she got pregnant through artificial insemination, though who donated the sperm remains unknown.
- Done with Lori Grimes from The Walking Dead. The truth is speculated on, but never revealed.
- When Anna finds out that she is pregnant in Northern Overexposure, she has no idea who the father is.
- The Tina Fey movie Baby Mama has a rare example of "who's your mommy" thanks to IVF.
- Bridget Jones' Baby centers on this trope.
- Buona Sera Mrs Campbell has Gina Lollabrigida trying to figure out which of three men is the father to her child.
- In the 1979 filmatisation of Hair, a major (and never resolved) mystery is who got Jeanie pregnant: Hud or Woof? In the finale (Let the Sun Shine In), Jeanie and Woof are cradling the baby, but it is never stated.
- In Local Hero, the protagonist asks a gang of punks whose baby is with them (the mother being the one female punk in town). They just look at each other.
- The Miracle of Morgan's Creek is an odd example: She bumps her head at a farewell party for draftees, gets married and pregnant in her temporarily poor judgment, and then never remembers who her husband is.
- Done very dramatically in Rob Roy, where Mary is uncertain if her baby's father is her husband, the titular character or his mortal enemy, her rapist Cunningham.
- In Mamma Mia!, Donna Sheridan had quick affairs with three different men, all of whom might be the father of her child, Sophie. Hilarity Ensues when Sophie invites them all to her wedding. Although the biological father is never revealed — according to the creators it's Bill — they each agree to be 1/3 a father to her.
- 3 Generations: It turns out Ray's birth father is not really Craig, but Craig's brother Matthew, as a result of Maggie's cheating with him. Due to this, Craig broke off contact with them. Worse yet, everyone but Ray knew, and didn't tell him.
- The Dark Tower.
- Was Susannah's baby from Eddie, or that incubus who raped her? It was the incubus, say sorry.
- For added fun, the kid actually turns out to have TWO daddies Roland, and the Crimson King. The incubus was just the delivery mechanism.
- In Jane Austen's Love and Freindship, Philander's and Gustavus's mothers were unsure of the paternity of their sons.
Our mothers could neither of them exactly ascertain who were our Fathers, though it is generally beleived that Philander is the son of one Philip Jones, a Bricklayer, and that my Father was Gregory Staves, a Staymaker of Edinburgh. This is, however, of little consequence, for as our Mothers were certainly never married to either of them, it reflects no Dishonour on our Blood, which is of a most ancient and unpolluted kind.
- Bree's pregnancy in the later Outlander books is a major issue, since she lost her virginity to her caring, gentle lover Roger, and was raped by Smug Snake Stephen Bonnet in roughly the same period of time. Indirectly, Jamie's other child, William, has the paternity quandary as well.
- This has fairly major significance in the backstory of the fantasy novel Song in the Silence. The debate is not the heroine's, but her mother's — since one of her lovers promised his first-born child to demons in exchange for a powerful magical artifact. The heroine decides not to go Gene Hunting, since she knows which of the men she thinks of as her father, and nothing else matters to her. Of course, the one who sold her soul is her biological father. Things just never work out well for fantasy heroes, do they?
- In the Thursday Next novel Lost in a Good Book, Thursday finds herself pregnant after the Chronoguard disrupts her personal timeline and worries that Miles Hawke, a man whose relationship with her is obscured by her Ripple Effect-Proof Memory, may be the father instead of her retgone husband Landen. The situation is resolved when Thursday learns that the relationship with Miles that she doesn't remember involves helping him conceal his secret relationship with her brother Joffy.
- In Twilight, this is a minor, unresolved subplot with Embry, who turns out to be a shapeshifter. The thing is, that power only passes from father to child, and the only shapeshifters who could have fathered Embry were married to women other than Embry's mother. It's an uncomfortable subject that most of the pack (some of whom, logically, must be Embry's half-siblings) tries to avoid.
- In Maurice Level's short story "The Bastard," a man becomes convinced that the young son he's raised isn't his and that his wife has been cheating on him for years, and throws the child out of the house. His paternal instincts kick back in after the boy is mauled to death by the neighbors' rabid dog.
- The Alice Network: Charlie slept with so many boys that she doesnt know who got her pregnant.
- The Forgotten Beasts of Eld: Tamlorn's father is unknown initially, as his mother was suspected of having an affair. The father was either her husband King Drede, or Coren's brother. It turns out to be Drede. She never managed to have sex with the other fellow.
- Every Soap Opera ever. Ever! So common that Soap Opera Digest actually needed to applaud General Hospital for avoiding this trope when Brenda slept with husband Jax and ex-lover Sonny.
- One particularly egregious example: on One Life to Live, Nora intentionally got pregnant by Sam and pretended the baby, Matthew, was Bo's son. Then everyone found out he was Sam's son. Then it turned out he was really Bo's son. Then it turned out he was really Sam's son. Then it turned out he was really Bo's son. Sam is now dead, so the volley is probably over.
- 30 Rock parodies and repeatedly mentions the Mamma Mia! example below.
- The Affair: Noah and Alison's affair eventually results in her becoming pregnant again. However, she also had sex once with her ex-husband Cole at the approximate time of conception, so isn't sure about the parentage for a while and keeps this from Noah. Later it is confirmed to be Cole's child through DNA tests taken during the trial.
- Cally on Battlestar Galactica (2003) hid the paternity test results from her husband. It wasn't until after her death he learned of it and shared the results with the biological father.
- This trope ccurs several times in Call the Midwife.
- In Series 1, the nurses encounter an older couple with a very involved father and a very detached mother. The baby is a Chocolate Baby, but the father calls him "the most beautiful baby in the world" and names him Edward Jr.
- In Series 2, Trixie and Sister Evangelina are called to deliver a baby on a Swedish cargo ship. They're confused at first because women aren't allowed on cargo ships. The expectant mother explains that her father is the captain, who brought her on board after her mother died... and pimped her out to the crew. All the sailors stand outside the cabin door while the baby is born and sing to their possible daughter when they hear her crying, but in the end the mother decides to abandon ship and give her daughter a proper life.
- In Series 3, a married woman asks for help secretly giving her baby up for adoption because it's not her husband's. Sister Julienne suggests that it would be kinder to let the husband raise the baby as his own, but the mother confesses the biological father was black. When the husband sees the little girl, he threatens to murder her, forcing Nurse Leigh to drag her from her mother's arms for her own safety.
- Sue Ellen became pregnant on Dallas after an affair with Cliff Barnes. Turned out the baby was indeed JR's. And they did it again years later when Cliff bumped into old girlfriend Afton and her daughter. Despite Cliff's hopes, this child too turned out to be someone else's daughter.
- Degrassi: When Clare finds out she's pregnant, she figures the father is Drew, a one night stand, because he was the last guy she slept with. A few weeks later at her ultrasound, she finds out she's further along than she thought, meaning the father is actually her ex-boyfriend Eli.
- The paternity of Aeryn's pregnancy became a prevalent source of angst during season four of Farscape. Thanks to Fantasy Contraception, Peacekeeper females can hold an embryo in stasis for up to seven cycles (years), so Aeryn had no way of knowing if the child was Crichton's until she made it to a medical facility near the end of the season.
- The Five: It turns out that Jesse was really fathered by Frank, a neighbor whom his mother had an affair with. She suspected he might be the father, but insisted otherwise to Frank.
- Friends: Played with. Erica doesn't know which of two men got her pregnant. The father is either a golden boy or an imprisoned murderer. It's resolved when she confides the details of her two relationships to Monica and Monica realizes that Erica's sex education must be severely lacking; what she did with the prisoner could never have gotten her pregnant.
- Blair on Gossip Girl nearly had one of these in S1 (turned out to be a false alarm) and then does have one in S5. Not that it lasts.
- Hollyoaks did a rather convoluted plotline where the mother of the child had a serious relationship with the guy who wasn't the father, but he was the only one who knew that he wasn't the father. Then the mother died and left him the baby, and he got together with the dead mother's sister (I know, c'est la squick) and their relationship ended horribly. So then they had a big custody war over the baby because of the complicatedness.
- The Jeremy Kyle Show does this a lot with DNA tests. "And the test reveals that John (thirty second pause) is the father of Jean's baby!"
- In the Lifetime Movie of the Week (of course) The Secret She Carried, a woman is raped and later finds out she's pregnant, but is uncertain if her husband or the rapist is the father. Adding to the drama is that by the time the pregnancy is advanced enough for her to do a paternity test, it will be too late for an abortion should the rapist be the father. As it turns out, her husband is the father after all, but in true Lifetime style, it doesn't stop the rapist from believing otherwise and promptly stalking and terrorizing her in an effort to claim "his" child.
- Lost: Sun had an affair before coming to the island, and had been told Jin was infertile. Thus Sun is not certain Jin is her baby's father until a sonogram in "D.O.C." shows the baby was conceived on-island (and Juliet reveals the island increases sperm count). The issue seems to be settled, but some fans suspected Michael to actually be the father. But in the episode "Ji Yeon", Sun gives birth to a baby girl that is completely Korean looking — not a lick of mixed racial heritage in her.
- Manifest: Grace is initially unsure whether Danny or Ben fathered her baby. It turns out that Ben did.
- Maury once had varied topics. Nowadays, the show mostly deals with nothing but women giving men paternity tests. Sometimes, one woman will take up the entire show testing seven or eight men, find out it's none of them, and return another day.
- The central concept of My Two Dads — the mother died without knowing who the father was, and a judge ruled both potential fathers had to raise the daughter together. Hilarity Ensues.
- Nip/Tuck has this with Julia and the paternity of Matt. After finding out that Christian is his father, due to a one night stand before Julia's wedding to Sean, she hides it from her husband. She reveals it to her son's father, her son, and her husband (in that order) causing her husband to kick her out. Her husband doesn't treat her son any differently and eventually forgives both his wife and his son's father for the affair.
- A subplot in Oh, Doctor Beeching!, involved a new station master at a rural English train station finding an old flame running the canteen. She has a daughter who could be the new station master's, and it turns out that the mother was seeing both her husband and the station master at the same time. The paternity was never disclosed, but was hinted to be her husband after all.
- Outlander: Brianna isn't sure whether her baby is Roger's, or fathered by her rapist, since the rape took place on the same day as her having consensual sex with Roger.
- On Peep Show there were at least three candidates for the father of Sophie's baby — Mark, Jeremy, and Jeff. Mark has claimed fatherhood on the basis of Sophie telling him DNA tests have revealed it is his.
- On The Secret Life of the American Teenager, there were two candidates for the father of Anne's son: her ex-husband George and her new boyfriend David. David had been told he was sterile, but George had gotten a vasectomy years earlier, so everyone assumed that David was, in fact, not sterile and the father. Then George confessed that he had lied about getting a vasectomy. This led David to conclude that George was the father. David broke up with Anne and left and that was that. We are initially led to believe that George is the father, but we later find out it's David.
- Sense8: Amanita's biological father isn't known, but all three possible guys love her anyway as her dad.
- This pops up with Claudia Black again in season 9 of Stargate SG-1. Vala, upon accidentally arriving in the Ori galaxy, finds herself pregnant with no explanation and gets married to avoid punishment from the incredibly religious townspeople. Vala and her husband do eventually find out that the child is "the will of the Ori", making Vala's pregnancy a rather dark take on immaculate conception.
- Played with when Vala tells SG-1 about it and they immediately assume she was just really promiscuous.
Mitchell: And I ask this not 100% sure I want to know the answer: Whose baby is it?
Vala: That's the thing: I don't know.
Carter: As in
Vala: I swear, I did none of the necessary bits.
- Played with when Vala tells SG-1 about it and they immediately assume she was just really promiscuous.
- Shows up in Supernatural of all places. Dean meets an old flame who has a son who acts and looks like a mini-Dean and was born roughly nine months after they were together. The woman assures him that the son is not his and the real father left them shortly after her son was born. Some fans, however, theorize that she was lying, although this possibility is never addressed in-show. Dean eventually settles down with them after Sam's death, but leaves when Sam comes back and winds up having Cas erase their memories of him to protect them.
- Terriers: Britt's girlfriend Katie gets pregnant shortly after a drunken one-night stand with her professor. Britt eventually finds out when he confronts her about why she hid the pregnancy from him. He's angry at first, but later asks her to throw away the paternity test results without looking, because he wants to believe the child is his.
- Another central concept of the trope — the Fox reality show Who's Your Daddy?. A person who had been adopted as an infant must pick out his or her biological father out of a group of 25 men. It gained a lot of controversy and massive backlash and was pulled off the air after only one episode. The remaining 5 episodes aired on their reality cable channel.
- A big part of the plot during season 8 of The X-Files. Though, being a paranormal show, and with Scully not actually supposed to be able to have children, it was both this and a 'How the heck did this happen?' It was later revealed that the Smoking Man had artificially inseminated her with his sperm.
- War of the Worlds (2019): Chloe was unsure initially of who fathered her son, because she had slept with a lot of boys and also been raped around the same time. After his birth, she realized her rapist was the father as they had the same eyes.
- Happened on The Archers, when Emma wasn't sure whether her baby was Ed's or William's.
- In Dishonored, the identity of Emily's father is deliberately kept vague, but is heavily hinted to be Corvo. Eventually, Word of God and the sequel outright confirm it.
- In Yakuza 6 Haruka had a child by the time of the game and a major plotpoint is figuring out who the father is. Eventually, it's revealed to be Yuta Usami, whose own secret heritage as the illegitimate son of a Chinese crime lord makes things even more complicated.
- This◊ Married To the Sea comic.
- In Something*Positive, Davan goes back home and has a one-night stand with an old friend named Donna. When he moves back home a few years later, Donna has a young son, Rory, and admits that she doesn't know for sure if the father is Davan or the guy she dated after their fling. A Daddy DNA Test shows that Davan isn't the father. He becomes Rory's Parental Substitute anyway, though.
- In the American Dad! episode "The Kidney Stays in the Picture", it's revealed that Stan may not be Hayley's father. The truth is never discovered or revealed, but Stan chooses to believe she's his, regardless.
- Played with on South Park in the episodes "Cartman's Mom Is a Dirty Slut"/"Cartman's Mom Is Still a Dirty Slut", where Cartman tries to figure out who his biological father is. It doesn't help that his mom Really Gets Around, and is also a Hermaphrodite. Episode 201 reveals that she lied about that last part, and it is, in fact, one of the Denver Broncos, and that Scott Tenorman, an older bully whose parents Cartman had killed and fed to him, is his half-brother.