Greyfarn (Farnsworth): She said he was a foul He-demon.
Ignus: Exactly. You are my father.
Greyfarn: No. No, that's impossible.
Ignus: Search your feelings. You know it to be true.
Greyfarn: No, no!
Ignus: Yah-hah. I heard Mommy say so.
Finding out parentage in a story can be shocking to characters, but so is finding out they are a parent. A character comes along, and suddenly turns out to be either a long lost child, or a child a character never knew he had. This is what you get when a Missing Mom or Disappeared Dad had no idea they were one in the first place.
This is of course the flip-side of Luke, I Am Your Father. Compare Separated at Birth, Luke, I Might Be Your Father. May result in Sink-or-Swim Fatherhood. Subtrope of Connected All Along. Supertrope of Your Son All Along, in which the character learns that they are the parent of a particular child. This is a Reveal Trope, so Spoilers will be coming your way.
- Angel Sanctuary. Angels aren't allowed to have children, so Zaphikel is tricked into killing his pregnant lover and brings his child's fetus to the breeding machine, to make it pass for a legal, artificially made angel. He's too late, the fetus is dead, so he tries to kill himself. Then Adam Kadmon shows up and saves him, but the sight of such a glorious creature leaves him blind. Years later, Adam Kadmon shows again and restores his sight, he takes a glimpse at his then assistant, Raziel, and instantly realizes that he is his son, Adam Kadmon had resurrected him back then and he didn't notice because he was blind. Then he dies.
- Dragon Ball Z: Trunks. Technically he's a Kid from the Future and Vegeta only found out their relationship after the Trunks of his timeline was born.
Vegeta: Wha-? "Trunks"? How bizarre, he has the same name as my son. Wait a second, a Super Saiyan from the future? Of course, it has to be! He's my son! Unbelievable!
- Fairy Tail:
- Cana's motivation for passing the S-class exam is so she can work up the nerve to tell Gildarts that she is his daughter. When she finally tells him, he immediately asks who her mother is, since he's slept with many women over the years.
- Averted by August of the Spriggan Twelve, the biological son of Zeref. While he knew Zeref was his father almost from since he was a little boy, he never told him throughout all the years he spent as a member of the Alvarez Empire, and was simply content with ruling alongside him as a comrade. Considering Zeref's complicated relationship with his lover Mavis Vermillion and brother Natsu Dragneel (August's mother and uncle respectively), this was likely a smart move on his part.
- In Mahou Sensei Negima!, the main antagonist of the Festival Arc is Chao Lingshen, who is eventually revealed to be a descendent of Negi's.
- JoJo's Bizarre Adventure does this three times: Josuke, the protagonist of part 4, is part 2 hero Joseph's long-lost son. Giorno Giovanna, protagonist of part 5, is the son of Dio Brando, and in part 6 we meet Dio's other sons.
- The entire premise of Otaku no Musume-san, where Kouta first learns he has a daughter, Kanau, when she shows up on his doorstep, with a note from her mother reminding him of a certain eventful afternoon about ten years before. Eventually it starts turning out that everyone is "related", too (mostly through things like adoption, marriage, and friendship), though it's one case that's not much connected to this trope.
- Subverted in SD Gundam Force. While Kibaomaru learns that Genkimaru is his son from Shute, he doesn't believe it until he remembers the Orphan's Plot Trinket.
Kibaomaru: That's why he had the dagger with my emblem... the one I gave to that woman...
- SoltyRei Roy Revant's daughter Rita Revant turns out to be Rose Anderson. Her hair and eye colour had changed due to exposure to nanomachines from the Blast Fall. Having been adopted by Larry and Andy's father with no memory of who she was, she initially resisted the idea that she was Roy's daughter until later.
- In Sunday Without God, Ai recognizes Hambart as her father from her mother's descriptions. He denies it at first, but realizes it's true when it turns out that Ai's mother looks exactly like the woman he's spent years looking for.
- The true Big Bad of the X-Men anime is revealed in episode 12 to be Professor Xavier's crazy Reality Warper son Takeo. Takeo's mother had told Xavier that his son was dead.
- Connor Hawke, the second Green Arrow, showed up in the '90s as the son the first Green Arrow, Ollie Queen, never knew he had. Retcons have since established that Oliver actually did know, and Connor knew Oliver knew, although Oliver didn't know that Connor knew Oliver knew. All clear?
- Wildcat IV in Justice Society of America.
- The JSA has a bit of a habit of this. Jade and Obsidian pulled this one on Green Lantern (Alan Scott) when they were first introduced back in The '80s.
- Captain Boomerang II in Identity Crisis. Includes the literal line, as when Captain Boomerang tracked down his son, put up for adoption, he lost his nerve at the last moment — too late to prevent his son from seeing him and making the jump.
- The Trickster in the DC Universe once went to help an ex-girlfriend whose son was in danger. After protecting him from the demonic Neron, he did the arithmetic to realize who the father had to be.
- In the new Booster Gold comics in which Rip Hunter, a character first introduced in the DCU in the 1950's, bullies Booster into being an unknown hero, there've been strong hints that Rip is Booster's son. From the future. Try not to think about causality too hard. Booster himself also crashes at his great-great-great-etc. grandfather's house.
- In Green Lantern Corps #35, it's revealed that Korugarian Green Lantern Soranik Natu is Sinestro's daughter.
- In Batman, Damian Wayne, son of Bruce Wayne and Talia al-Ghul, was raised in the League of Shadows since birth with his father never knowing about him until years later.
- He made his grand entrance by beating the shit out of Tim Drake, the current Robin, in the apparent belief this would make him Robin. (Jason Todd expressed his return to life by beating up Tim. Tim is kind of the Butt-Monkey of the batfamily, which is saying something since Jason got killed and Barbara crippled.)
- Damian was retconned into being a Child by Rape via Talia drugging Bruce, and then, by the way, she put him into a Uterine Replicator as soon as possible so being pregnant wouldn't have the chance to ruin her body. (It often does that and she's put everything into her physical prowess.) This comes up when it turns out she's given him up as corrupted by Batman's ethics and is replacing him with a clone.
- Professor X was shocked to discover in New Mutants #26-#28 (published 23 years after his first appearance) that he had a son in the extremely powerful mutant Legion aka David Charles Haller. Up until then he had assumed David to be the son of a dead friend.
- Wolverine turned out to have both a gender-swapped clone (Laura Kinney, aka X-23), and a long-lost son, Daken. Hell he's even come across an entire team of his children sent to kill him that he didn't know about until after the fact.
- The new Scorpion is the daughter of villainess Monica Rappaccini, probably fathered by Bruce Banner (aka the Hulk). Speaking of the Hulk, he also has his son Skaar, who was still in his mother's womb when she died, as well as Lyra, his daughter by Thundra from a divergent future. There's also Skaar's twin, Hiro-Kala.
- Darkdevil in Spider-Girl, who is revealed to the reader - but not the heroine or her family, yet - to be the son of Ben Reilly, Spider-Man's clone.
- In "The Long Cold Dark" story arc of The Punisher MAX, Frank Castle discovers that Kathryn O'Brien gave birth to his daughter before she died. His recurring foe Barracuda kidnapped her to get to him. Needless to say, Frank was pissed.
- In Young Avengers Presents: Hulkling, Hulkling does this to Captain Marvel. Who turned out to be a Skrull anyway. Awkward.
- Wanda and Billy, in The Children's Crusade, because Wanda has lost all her memories.
- The Grievous Journey of Ichabod Azrael: The native girl Ahtunowhiho tells Ichabod Azrael that she's his daughter by Zoe. The characters themselves lampshade how out of nowhere this reveal is and perhaps the result of a writer running out of ideas.
- During the "Salvation" arc or Preacher Jesse becomes acquainted with a woman named Jodie, whose demeanor and appearance bears an uncanny resemblance to the deceased Jody from previous arc "All in the Family". Jesse begins to feel that something is amiss about Jodie beyond the obvious the more time he spends with her, until it finally hits him one night while alone with her in her bar and he can only say one word: Mom?
- Star Wars: Darth Vader: Issue #6 shows the exact moment Vader figured out who Luke Skywalker was, when Boba Fett, who Vader had hired to capture the Rebel pilot who destroyed the Death Star, reports that he didn't get the kid, but did find out his name:
Vader: Did you bring me anything of value, bounty hunter?
Fett: Not much. Just his name. Skywalker.
[Vader is silent, staring out the window in front of him into space]
Fett: We're done here, then.
Vader: [still staring out the window, which is cracked all over, as his hand shakes with Force energy] Skywalker.
[He folds his arms, remembering past events — Padmé crying, Padmé's funeral, his first encounter with Luke]
Vader: I have a son.
[the window glass is almost completely gone]
Vader: He will be mine. It will all be mine.
- In Tom Strong, Tom's evil neo-Nazi son Albrecht, who was conceived when World War II-era Third Reich science-villainess Ingrid Weiss drugged Tom and stole a sperm sample from him, then impregnated herself. He only found out when the mother-and-son duo tried to kill him fifty years later.
- Tossed in a blender with Luke, I Am Your Father (but not really) in Usagi Yojimbo: Usagi discovered that his old flame Mariko's son Jotaro is actually his son, and Mariko's husband (Usagi's very unfriendly rival) also knows but loves Jotaro anyway. Usagi and Jotaro's sword master guessed almost immediately (they're very much alike), and gives them the opportunity to travel together for several months; after talking with Tomoe about responsibilities and relationships, Usagi decides not to break the bond between Jotaro and his family, while Jotaro decides not to force Usagi to give up his wanderer lifestyle to take care of him. It turns out Mariko told Jotaro the truth, but left out the part about Usagi knowing too. Upset at his "weakness" and the fact that he doesn't know when or if he'll ever see his "uncle" again, Jotaro calls out "Miyamoto Usagi! You are my father!!" but Usagi is already too far away to hear ("Just a trick of the wind, I must be tying my ears too tight"). TL;DR: Father A and Son B know the truth, but each doesn't know the other knows the truth (C,D,E, and F know the truth too, but they aren't talking, mainly out of respect).
- Semi-Lampshaded in the newspaper comic strip FoxTrot, in which young nerd Jason campaigns for Lucasfilm to digitally insert him into the Special Edition Star Wars films as Luke's younger brother. Obviously, this goes nowhere. ("At least they sent back my Darth Jason prototype action figure.")
- Child of the Storm has, in chapter 80, Carol Danvers reveal to Steve Rogers that she's his great-granddaughter, something she'd only just found out herself.
- When Asa in Futari Wa Pretty Cure Blue Moon first starts to wonder about Enigmatic Minion Mekuramast's true motives, her initial conclusion is that he's her Disappeared Dad, and she confronts him about this. As this theory is purely born of Asa's Wrong Genre Savvy and, more to the point, makes no sense, it's quickly refuted, and he spends the rest of the story thinking she's a nutcase.
- Day 1 of One Hundred Days has Warp Darkmatter telling unmarried and virginal Buzz Lightyear and Mira Nova that they're his parents, and he has proof to boot. Turns out, he's right!
- Who Is Voldemorts Dad? The Tales of Vernon Dursly! by the infamous D'arkYagam'i is exactly what the title implies.
- Emergency!: John Gage finds out in "Lost and Found" that his girlfriend had his child while he was being held captive and gave her to Roy and Joanne. They begin raising her as theirs, and when John is found alive and brought home, Roy has such a hard time figuring out how to tell John that he figures it out himself when he sees his mementos and pictures in the baby's room.
- Lucina Reacts: The newcomer Fiora turns out to be Emmeryn's daughter. Most of the people present are understandably shocked.
- The Star Trek Online forums' Unofficial Literary Challenge #27: "Extra Lives" used this as a prompt (titled "Vader, I Am Your Son"). Entries included "Brother on Brother, Daughter on Mother", which contains the following lineexplanation :
"Belka Saris": I'm Commander Reshek Taryn, Starfleet Intelligence Special Operations Section Eight.
Kanril Eleya: Reshek? (looks at her husband Reshek Gaarra) Gaarra, I didn’t know you had any other relatives in the service.
Reshek Taryn: Neither did he, ma'am.
Taryn: Captain Kanril, I'm your daughter.
- The Bridge: Commander Hurricane fathered Ardent Sentry after a one night stand. Ardent did not tell him about their relationship until after she had distinguished herself as a soldier, so that she could prove she got where she is on merit instead of nepotism.
- Shudo cross Modern Ash: The Professor Who Observes his Charges has Professor Oak and his son, Daisy and Gary's father. The son's father never contacted Oak, and when he did find out the son had no interest in reconciling.
- Aladdin and the King of Thieves: Happens when Aladdin meets his father Cassim. Cassim is convinced by the dagger Aladdin is carrying - he had left it with his wife to give to their son when he was old enough.
- In Beowulf, the Dragon reveals to Beowulf that he is actually the hero's long-lost son from his deal-with-the-devil dalliance with Grendel's Mother.
- Cornelius "Lewis" Robinson to Wilbur from Meet the Robinsons.
- Miguel to Ernesto de la Cruz in Coco. The latter is surprised that he has a great-great-grandson, which is foreshadowing that de la Cruz is not Miguel's ancestor.
- Blade Runner 2049 sets this up when K meets with Deckard, but subverts it by never actually making the revelation. Then it's even further subverted when we find out that Deckard's child was a girl.
- The Reveal in the slasher film Cherry Falls. The Serial Killer targeting virgins Marliston is strongly implied to be the son of Sheriff Brent conceived through rape 25 years ago, making him the protagonist Jody's older half brother.
- A Dog Of Flanders — Nello tells Michel that he's Nello's father.
- There's one implied at the end of Dream Girls, when Magic finally meets his father, who is understandably quite shocked by this revelation.
- Forrest Gump finds out he has a son via Jenny. Epileptic Trees say this might not be the case, but Forrest is the only reliable parent Jenny can find.
- As Indiana Jones and Marion Ravenwood are sinking into sand in Indiana Jones and the Kingdom of the Crystal Skull, she reveals Mutt Williams is his son. Hilarity Ensues. It's also Luke, I Am Your Father at the same time.
- Kill Bill's Twist Ending, in which Beatrix Kiddo discovers that her daughter is still alive.
- Parodied in Jane Austens Mafia, when a woman meets a young boy at a party.
Diane: So, what's your name?
Diane: Like me!
Anthony: I named him after his mother.
Diane: I'm a mother? Why didn't you tell me?
Anthony: You said you didn't want to be a part of my life.
Diane: Oh! Anthony, he's the most beautiful thing I've ever seen! He looks just like me!
- In The Long Kiss Goodnight, the Big Bad is about to leave Charlie and her young daughter to freeze to death in a meat locker. Charlie, in an attempt to save her daughter, reveals to him that her daughter is also his daughter. He leaves them both in the locker anyway.
- The main plot of Matchstick Men revolves around this. It's actually a con, though.
- Oldboy (2003) features a particularly cruel example: the main character is the victim of an elaborate revenge/imprisonment plot, the final result of which leads him to discover that the young woman he fell in love with and just had sex with is his long-lost daughter. The Reveal had such a big impact on him that he cut off his own tongue and went to a hypnotist so he could forget. The villain really out-did himself with his revenge.
- In Terminator Genisys, the assimilated John Connor reveals to Kyle Reese that he is his son in 2017. Kyle is understandably shocked.
- Wasabi: Jean Reno's character discovers he has a Japanese daughter.
- The Wicker Man (2006): Willow reveals to Malus that yes, Rowan is his daughter, after he gets suspicious. The islanders apparently believe it was necessary to have a sacrifice with a blood connection to one of their people.
- X-Men Film Series
- X-Men: Apocalypse: Subverted. Peter Maximoff knows by now that he's the son of Magneto, and he was about to tell the latter in a scene during the climax, but at the last second, he did not do it.
- Logan: Laura herself doesn't tell Logan he's her father, but Charles announces it after they escape the Reavers. Gabriela confirms it when he watches the video she left him in the event of her death, and just to be sure, it's clearly noted in her medical file that his DNA was used as donor material.
- The plot of The Game Plan kicks off when a girl arrives at the home of football star Joe Kingman and tells him that she's his daughter from a relationship he had years ago.
- In The Chronicles of Amber, this happens to Random, as well as to Benedict (who finds he has a great-granddaughter, Dara), and Corwin (who finds he now has a son by Dara).
- To their credit all three men promptly go all Papa Bear upon discovering their offspring. As Corwin's sidekick observes "Paternity hits you lot hard."
- William Butler Yeats wrote a poem, Cuchulainn's Fight with the Sea, in which Cuchulainn's son leaves home with a vow (apparently designed to give him extra chances to get into fights) not to give his name but at sword-point, that is, after being beaten, and only against someone who's sworn the same. He runs into Cuchulainn in short order, and as Cuchulainn has been under the same oath since childhood they have an epic fight. Cuchulainn gives him a chance to withdraw and live, and says his head looks like 'a woman's head that I loved once.' Then he gets into his berserk mode and mortally wounds him, and demands his name before he dies. And he's Cuchulainn son of Cuchulainn. He is stricken. The people he was partying with earlier predict that once he's done mourning he'll kill everybody to work off his feelings, so they get the druids to enchant him so he gets in a fight with the ocean instead.
- The kicker is that it was Junior's mother who told him to make the vow and go to the precise place Cuchulainn was to be found, thereby guaranteeing them a fight in which the father didn't know he was killing his son. Apparently based on an actual myth/saga thing in which this happened to Cuchulainn, only in this one his wife was actively trying to get revenge on him for leaving her through their son.
- Dragonlance: Averted in Dragons of Summer Flame by a character raised by a race of island dwelling fae who is mistaken for Raistlin Majere's daughter. She seeks him out, and he promptly tells her she's mistaken.
- The Dresden Files: Book 12, Changes, kicks off with Harry receiving a phone call from his old flame Susan Rodriguez, who he hasn't seen in years. The subject of the call? "Harry, they've got our daughter." They being the Red Court of Vampires, who are currently at war with the White Council of Wizards, to which Harry belongs. Harry responds to the news of his sudden fatherhood by going to MacAnnally's pub in shock.
- Dune had Baron Harkonnen learning immediately prior to his Karmic Death that the girl who poisoned him was his granddaughter. His reaction in the miniseries makes it pretty clear that he was extremely shocked that she was his relative. Her mom, BTW, was the byproduct of a rape from him by one of the witches.
- Considering the Baron's preferred sexual partners were young men, the Bene Gesserit witch had to use some coercion to make him rape her, as part of the Bene Gesserits' long-term breeding plans. The Dune series is very weird sometimes.
- In The Fire-Us Trilogy, one of the characters reveals to the audience and his father to be one of the President's sons, presumed dead for years. Interestingly enough, he may or may not have known it himself for most of the series. Our protagonists are damaged goods.
- The Hitchhiker's Guide to the Galaxy: Random does this to Arthur Dent in Mostly Harmless.
- In John Devil by Paul Féval Henri tells Temple at one point that The Killer, John Devil, is actually his half brother, Tom Brown, who he claims is Temple's son by an adulterous affair with Helen Brown. This is most likely all a complete lie however, it doesn't fit the total fact.
- Kafka on the Shore, a novel by Haruki Murakami. The relationship is not spelled out but rather strongly implied, in the manner of: "Are you my mother?", "Why, you have to ask?"
- The rare gender inversion is found in The Lost Stars series, precipitated by Sci-fi technology: When the ever-suspicious Morgan finally gets evidence that her co-adviser Malin has been acting behind their leader, Arthur Drakon's, back by falsifying his official DNA records, Malin explains to Drakon one-on-one that this was done by his "mother" to hide his real parentage: Morgan. His mother was a doctor examining Morgan before she left on a suicide expedition into alien space using cryogenic technology to survive the time it would take to arrive. She discovered Morgan was pregnant, and being barren herself, secretly acted as a surrogate for the child, who was Malin. Morgan was eventually recovered but left otherwise unaware of her child, who tracked her down out a sense of duty, only to find she was psychotic and then stuck around to protect her and protect everyone from her. Drakon is thrown through a loop by the revelation, especially because Malin is the polar opposite the gung-ho, emotionally manipulative Morgan and a biological year older than her due to the cryogenic shenanigans. They both agree that Morgan can't know, as the shock of it would likely drive her to kill Malin outright, given their otherwise already near murderous rivalry.
- In Brandon Sanderson's Mistborn, Vin identifies her long-lost father, since her brother had pointed him out to her. The father didn't know she existed until she pointed him out to his boss.
- In Michael Crichton's novel Next, one random story involves a man working somewhere. A young woman with a baby walks up to him and claims to be his daughter. Naturally, he doesn't believe her. She then reveals that she went through a long and arduous process to find out who donated sperm to her mother, despite the fact that it was supposed to be anonymous, spending years just to discover her dad. And then berates him for donating "defective DNA".
- Dirk Pitt Adventures: Dirk Pitt ended up with twins after it emerged that his girlfriend hadn't actually died. He becomes a good father really quickly.
- In The Heartstrikers, the Golden Emperor finds out that Bethesda's F-clutch of dragons is actually his with Chelsie, Bethesda's daughter, and moreover that he is entirely responsible for the pregnancy because his luck magic overcame the fact that the pregnancy was physically impossible. It does not go well. But it gets better. Briefly, that is.
- In Redeeming Love, Broken Bird Angel gets revenge on the father who abandoned her and allowed her to be sold into prostitution by sleeping with him and then revealing that she is the daughter he hasn’t seen in eight years. This is a major factor in his subsequent suicide.
- In Shaman Blues, at the end of the first part of the story Konstancja sends a girl to Witkacy's house. Incredulous, he's quick to figure out the kid is his teenage daughter, and the tyke herself quickly confirms it.
- Michael Flynn's Spiral Arm: In Up Jim River, Donovan is in denial, and the harper doesn't want to talk about once she realizes. When Donovan puts it together, the conversation that ensues has both this, and Luke, I Am Your Father.
- In a Star Trek Expanded Universe novel, the character Xyon is introduced at the beginning of the story and helps save the day. At the end, he punches out The Captain Mackenzie Calhoun before informing him his full name is Xyon of Calhoun. Nice first impression.
- Star Wars Legends:
- Averted in many, many ways in Legacy of the Force, ironically with the prospective father being Luke: Luke and Mara think that "Brisha"'s mother is Luke's ex-girlfriend Shira Brie. Mara asks Luke "Who is Brisha's father?" Luke replies "How should I know?", realizes what Mara's asking, and says their relationship was emotional, (even if it was based on her lies that almost got him killed) and never physical. Oh, and Brisha is Shira, a.k.a. Lumiya.
- In Poul Anderson's Time Lag, realizing that Elva feels a Fish out of Temporal Water, her rescuers quickly tell her that her son did indeed survive, and that one rescuer is her grandson — he quickly takes her hands — and she, indeed, has an infant great-grandson.
- Fred Vargas' Commissaire Jean-Baptiste Adamsberg has a one year-old son with Camille, but also a twenty-seven year-old son, Armel, whose existence he ignored until Armel, at the time believed to be the Zerquetscher, told him while threatening him with a gun in An Uncertain Place.
- In Void Moon, Karch tells this to the man he is murdering, right before Karch shoots him in the head.
- The novel Sunrise in the Warrior Cats series, when Hollyleaf announces not only to her father, Crowfeather, but to the whole gathering of cats that Jayfeather, Lionblaze, and Hollyleaf are actually Leafpool's kits, not Squirrelflight and Brambleclaw's, and he's their father.
- In the mini-series The 10th Kingdom, a gender-flipped version occurs. Virginia has to tell the Evil Queen that she is her daughter. The Queen has no memory of her daughter but slowly begins to remember bits and pieces of the past. Including that she once tried to drown Virginia in a bathtub before she found the portal to the Nine Kingdoms.
- In a rare female version, Ally McBeal opens her door once to find a young girl there who said that Ally was her mother. Seems Ally had once donated an egg for research, and due to a mishap, this girl is her biological daughter.
- In Believe, the audience learns Tate is Bo's father at the end of the very first episode — they don't until the seventh, however.
- Beverly Hills, 90210: Gina was introduced in the later seasons as Donna's wrong-side-of-the-tracks cousin related through her mother's sister. With the help of some nifty software that included every single birth certificate ever made, Donna discovered Gina and Donna share the same father, making them half-sisters raised in separate homes.
- In the French series Les Bleus, Premiers Pas dans la Police, rookie detective Laura Maurier is the daughter that police chief Santamaria never knew he had, and she eventually tells him so.
- Buffy the Vampire Slayer: Twilight does this to Buffy and Angel.
- In Season 10 of Criminal Minds, Rossi discovers that he has an adult daughter by his second wife — as well as a son-in-law and a grandson — and welcomes her into his life, even helping her with one of her investigations.
- CSI: Miami, Horatio and his son.
- CSI: NY, meanwhile, has a variation with Mac finding out he has a stepson. His late wife gave birth as a teenager and gave the boy up for adoption. He came looking for her later, and though Mac had to tell him she had died, he still eventually formed a friendship with the kid.
- Doctor Who:
- "Father's Day": Rose goes back to when she was a baby and saves her father. She has to fend off some flirting from him right at the start, but he eventually figures it out more or less on his own. Later, after overhearing that the nineteen-year-old Rose is Pete's daughter but missing the "from the future" part, her mother is understandably squicked by the appearance that her husband a) fathered a child when he was about twelve and b) gave her the same name as the baby they currently have together.
- Then, in "Rise of the Cybermen"/"The Age of Steel", Rose crosses over into a parallel universe where Pete's alive but never fathered a child with Jackie, and we go through it all again, this time with Pete having to come to terms with the fact that he has a daughter in a parallel universe with the same name as his dog. Given that he just lost his wife and still has a lot of world saving to do, he elects to not to deal with it and runs away from Rose when she tells him.
- In "A Good Man Goes To War", River Song informs Amy and Rory that she is their daughter Melody Pond. She tells them this after her newborn self is kidnapped.
- Earth: Final Conflict: Liam "Kincaid" is the Child by Rape of Agents Sandoval and Beckett by Ha'Gel. He knows this, but his mother was mind-wiped to prevent her from exposing the Resistance. Beckett only finds out when she's dying from a CVI breakdown. It's a good question as to whether or not Sandoval figured it out.
- In one episode of The Fresh Prince of Bel-Air, a young man appears at the Banks' doorstep and introduces himself as Geoffrey's son. Apparently Geoffrey's ex-wife had given birth to him after their divorce and didn't bother to inform Geoffrey.
- In General Hospital, after seeing Bobby bond with her baby son Michael, Carly blurts out that they're mother and daughter. Considering Carly had single-handedly ruined Bobby's life — such as stealing her husband and suing her for custody of Lucus on the anniversary of BJ's death just to name a few things — Bobby is less than pleased with this news.
- On Gilmore Girls, there is a situation which could be (but isn't) the source of this trope name. A girl shows up in Luke's diner saying she is doing a science fair project in genetics to find out who her father is by testing the three guys her mother dated around the time she was conceived. It turns out Luke is her father. This is used to derail the upcoming wedding. Lorelai's father semi-lampshades this when discussing insurance with them and warning about tricksters and grifters, saying "It's just that the timing is a little suspicious..."
- Home and Away added an extra twist: John Palmer has a daughter named Shandi, but the Shandi he met was an impostor. Eventually, the real Shandi had to show up.
- Law & Order: Criminal Intent: Bobby Goren has just discovered he has a nephew (son of his junkie brother Frank.) Bobby wants to parent the kid but the kid is currently missing and on the run from the cops. Bobby's family is messed up.
- Bobby also learns that the man he *thought* was his father wasn't - his real father was a notorious serial rapist and killer.
- The protagonist of Life Unexpected is a 16 year old girl that was never successfully adopted that seeks emancipation and reunites her birth parents who a judge makes them their legal wards after deeming she is unfit to be emancipated, her father thought she had been aborted and when he was told in the first episode he had a daughter it was an instance of this, the girl's father is just a friend of the girl's mother as she has a fiancé of her own.
- Alex in Lost. Oh, come on, we all knew the moment the name came up.
- And of course there's Daniel Faraday, telling Eloise "I'm your son" right after she had shot and killed him
- MacGyver (1985)'s illegitimate and previously unknown son Sam shows up in the last episode, and demonstrates that Lamarck Was Right.
- At the end of the second series of Merlin (2008), Merlin meets his long-lost father, Balinor, for the first time. Balinor had no idea he had a son.
- Morgana says this sort of thing to Uther at the end of the third season, though he already knew. It was a Luke, You Are My Brother for Arthur, though.
- In Series 4 Episode 5 of Misfits, Finn tracks down several men with whom his mother Mary was intimate around the time of his conception to determine which of them is his biological father. To Finn's embarrassment, most of the men rule themselves out by claiming to have only engaged in sexual activity with Mary that was unlikely to result in a child.
- Emma Swan from Once Upon a Time gets this from both ends. On her twenty-eighth birthday, as she blows out the candle on her cupcake, she wishes she wasn't alone. Seconds later, she gets a knock on the door and finds the son she gave up for adoption when he was born ten years ago. He convinces her to follow him back to his hometown of Storybrooke, Maine, a small town populated entirely by fairy tale characters who have been cursed to forget their own identities. Among them, Emma finds her parents, Snow White and Prince Charming, neither of whom remember ever having a child. Because time flows differently there, they don't look any older than Emma, so she'll have to find a way to restore their memories before explaining the truth.
- One Quantum Leap has Sam leap into a rock star who's about to be murdered. One of the possible suspects is a teenage boy who's been hanging around at their concerts. He later gets Sam alone and reveals that he believes the rock star to be his father, conceived with his late mother after a concert. After the murder is thwarted, the boy meets the rest of the band and tells them why he's there. Another band member then subverts this when he reveals that the rock star got so drunk at the concert in question, he had to be taken to the hospital immediately afterward. Sam then tries to console the kid and says he would be glad to have him as a son. The other band member then looks at a picture of the mother and recognizes her as having had sex with the singer before the concert. Double subverted.
- Red Dwarf did a weird variant on this where Lister ended up fathering a kid... who later turned out to be himself through Applied Phlebotinum time travel. (Don't ask. It's Red Dwarf. What do you want, logic?)
- This is likely based on Robert A. Heinlein's famous Stable Time Loop story —All You Zombies—, about a time traveling hermaphrodite who ends up being his own father, mother, child, lover and the guy who convinced him to take up time travel in the first place. Time travel can be like that.
- There's another example of Luke, You Are My Father in the Red Dwarf novel Last Human, with the character Michael McGruder.
- In an episode of The Ropers, a 30 year old man tells Stanley that he is his son.
- Slasher: It turns out that Sarah's real father is Tom Winston, the man responsible for killing her parents, since he had an affair with her mother Rachel. He already knew, but she figured it out on her own before confronting him with this information.
- In Sleepy Hollow it is revealed that Henry Parrish is actually Ichabod and Katrina's son Jeremy, who was thought dead. He's also the Horseman of War, having been driven crazy spending 200 years buried alive and then resurrected by Moloch. He is hell-bent on getting revenge on his parents for abandoning him, although Ichabod at least can't be blamed for that since he died before Jeremy's birth, and Katrina was banished to purgatory by the same coven of witches who later buried Jeremy alive.
- In Star Trek, both Kirk and Picard had plots where they discovered their sons. Picard's son wasn't, Kirk's was (and Kirk knew about him, but the audience sure didn't).
- Worf also got two (sort of), the first in which he had no idea his one night stand with the half-Klingon ambassador had any results and then she showed up with their son, and the second in DS9 when said son shows up to serve the Klingon Defense Forces on Worf's ship with no warning.
- In DS9, a subversion occurs. Garak can only get Tain to drop the superior officer/inferior officer and mentor/protégé "formalities" of their relationship and behave as a genuine father and son when Tain is on his deathbed and even then Garak has to fight Tain into submission over it. The subversion comes from the fact that Tain and Garak have known the true situation between them for Garak's entire life, but there was no public acknowledgement of it because Tain feared having a biological son was a weakness someone in his position couldn't afford. He uses his dying breath to admit he was proud of Garak which is all Garak really wanted to know.
- Subversion, maybe: In a Supernatural episode, Dean goes to revisit the site of a 9-years-ago one-night stand and discovers that the woman has an 8-year-old son with remarkably Dean-like mannerisms. She swears the kid isn't his, and claims that DNA evidence proves it, although it is not actually presented to him. The creator later confirmed that the kid wasn't Dean's son.
- A variation in Season 4, where a guy a few years younger than Sam and Dean shows up claiming to be John Winchester's son. He actually was John's son, but it doesn't matter, since he was dead the whole episode anyway.
- Angels sure fixed that. Don't look like that. The guy got resurrected only to either force Dean into saying yes to Michael or to do it himself. He shows up as Michael's meat suit in the last episode. He, Michael, Lucifer and Sam fall into the pit. Sam's body gets out, but his soul is stuck behind with the rest of them, and when Dean asks Death to retrieve the brothers, he's given a choice of saving Adam or Sam's soul. Since Dean doesn't really have any leverage to begin with, he picks Sam.
- And then again in Season 7 in which it's played straight. Dean fathers an Amazon, who is Brainwashed and Crazy and sent to kill him in order to fulfill a coming-of-age ritual. At the end of the episode they get into a stand-off and Sam kills her to protect Dean.
- A variation in Season 4, where a guy a few years younger than Sam and Dean shows up claiming to be John Winchester's son. He actually was John's son, but it doesn't matter, since he was dead the whole episode anyway.
- Suspects: In series five, Jack discovers his girlfriend from his teen years, while in prison, gave birth to his daughter. The ex and the daughter are intricately involved in the crimes being investigated.
- Tyrant: Jamal finds out from his mother that he has a now-grown son, a decorated officer named Rami Said, from a short-lived relationship he had with a woman from the Rashid clan. His wife at first refuses to allow her husband's bastard into the palace, but later relents when she realizes that they need him to run Abbudin's military and perhaps save their regime from the Army of the Caliphate.
- Daniel Meade of Ugly Betty recently discovered that he had a son.
- Except that it was recently revealed that the father is really Daniel's brother Alex (who is now Daniel's sister Alexis).
- And then by the end of series, both were Putona Bus and never heard from again.
- Except that it was recently revealed that the father is really Daniel's brother Alex (who is now Daniel's sister Alexis).
- On The Vampire Diaries Elena discovers Uncle John is her father and uses this knowledge in a confrontation to force him to let her go.
- Hemlock Grove: In season 3, Annie reveals that she's Olivia's daughter, the result of her brief romance with a gypsy boy centuries ago.
- Ash vs. Evil Dead: Ash finds out in the season 3 premiere that he has a daughter, Brandy, from a one-night stand he had with a woman in town. Parodied in an Imagine Spot the next episode when he worries about the possibility of numerous other children he didn't know about showing up on his doorstep, all with a shit-eating grin on their faces.
Ash: Jesus in Anaheim!
- Johnny Cash's "Boy Named Sue" pulls this on his father, who he is hunting down to kill him for, well, naming him Sue.
- Cuchulain and Connla, in the Ulster cycle of Irish myth.
- Similar is the story of Sohrab and Rustum. Rustum, the Persian Hercules, has fathered a son but received the news that it was a daughter (so that he would not drag the son off on dangerous adventures). As a young man, Sohrab goes off looking for his father, and ends up fighting against him in a champion-versus-champion confrontation between two warring armies. Sohrab gives out that he is looking for Rustum, but Rustum conceals his identity as he feels it beneath him to be acknowledged fighting a lesser man one-on-one; and also because he thinks Sohrab is only glory-seeking, and will make peace and go away boasting of having met Rustum as an equal. Only after Sohrab is fatally wounded does he learn Rustum's identity and offer his father proof of his ancestry, eventually convincing him. Written up by Victorian poet Matthew Arnold based on the Persian original, see http://www.victorianweb.org/authors/arnold/pva356.html.
- Older Than Feudalism: In Greek Mythology, Theseus pulls one on Aegeus when the former enters Athens as a badass victorious hero. Aegeus's wife is not very pleased.
- Various interpretations of Beowulf hint at Grendel being Hroðgar's son and also though never outright stated in the text... Beowulf is the Dragon's father. Explicitly interpreted in the 2007 animated film. Grendel's mother is the seductress.
- In various medieval legends, Helena was separated from her husband and supports herself and her son until young Constantine's grace and charm draw his father's attention, leading to the revelation that he is his son, and a parental reconciliation.
- In some versions of the Arthurian mythology, Mordred is the son of Arthur and his sister, who was sent away to die as an infant, as he was destined to kill Arthur later on. Which he did when he showed up as an adult. It can also be a Self-Fulfilling Prophecy in some stories, as Mordred grows to hate Arthur precisely because he did this.
- In Battle Tech, Kitsune Kurita, son of Omiko Kurita and grandson of Coordinator Theodore Kurita, publicly revealed to Victor Davion that Victor is his father due to a clandestine affair, which his conception from was concealed from Victor. By that time, Davion/Kurita relations fostered by mutual enmity with the Clans had degraded, and the propaganda on both sides exploded over the revelation. A conspiracy to mount a coup against the current Coordinator using Kitsune as the replacement was quashed since their "heir" was revealed to be "poisoned" by Davion blood, and the Davions portrayed Omiko as a salacious Kurita harlot that tried to corrupt Victor. Vic was just happy that there was some legacy of his love for Omi, who was claimed by assassins from Victor's sister, Katherine. There was a bit of Foreshadowing involved with his name: His paternal grandfather is Hanse "The Fox" Davion, the premiere Magnificent Bastard in his day, and "Kitsune" is japanese for "Fox".
- Slightly subverted in Ever17, as the character in question already knew. It didn't stop her from fiercely denying it when her estranged children confronted her, or being a bitch to them before they worked it out. Played straight with the other character, who reacts typically for someone his age to the news.
- Throughout Jade Empire, it's slowly revealed that Dawn Star is Master Li's daughter. When you confront him with this, his response is approximately, "So what?"
- In Lost Odyssey, the pair of Tagalong Kids that Kaim and company befriend bring the party home to meet their ill mother... who immediately recognizes Kaim as her long-lost father, making the kids his grandchildren.
- In Sacred 2, the class-quest of the Inquisitor involves you running into your long-lost daughter, with a number of interesting consequences. Firstly, being a man of the cloth, you're not supposed to have children at all, and so you must keep the matter quiet and kill anyone stupid enough to try and blackmail you about it. And secondly, you have to Pet the Dog and keep your daughter out of the trouble she constantly finds herself in. Funnily enough, when she finally finds out that you're her father, she's... less than pleased.
- Fire Emblem:
""When I was under the control of that evil blade...I met my father in a dream. I was still little when I was separated from my father, but I still remember him. He was strong, kind, and gentle... Galzus... You're my father!"
- If you didn't kill him when he was your enemy early in the story, Mareeta from Thracia 776 recruits her until-then Disappeared Dad Galzus by telling him this.
- At the end of Metal Gear Solid 4, Jack aka Raiden gets his happy ending when he learns that Rose didn't suffer a miscarriage, and that Rose and Campbell's marriage was a sham to protect his son from the Patriots. Even better, his son John isn't afraid of Jack's cyborg body and thinks that his father is awesome.
- In Dragon Age II, Hawke's uncle Gamlen can learn that he has a daughter at the end of the quest "Gamlen's Greatest Treasure".
- Roger Jr., Roger's son from the future in Space Quest IV: Roger Wilco and the Time Rippers.
- The ending of Stubbs the Zombie reveals that Stubbs and Big Bad Andrew Monday are father and son respectively, with Maggie Monday having slept with the then living Edward Stubbleton before he was gunned down by her father (this also explains why Stubbs is so madly in love with her). Needless to say, the son is disgusted to learn this.
- Spoofed in Portal 2 with the insane ramblings of the Space Sphere, who insists that Space is his father and "now [they] are a family again".
- In Steins;Gate, Suzuha is looking for her father in 2010. Mayuri figures out it's Daru.
- The ending of Bioshock Infinite reveals that Elizabeth is actually Booker's daughter Anna that he once sold to Comstock as an infant to deal with gambling debts. His attempts to save her at the last moment is why she lost her pinky finger, having lost it due to a Portal Cut as the Tear between Booker and Comstock's worlds closed.
- Averted in Burial at Sea, the two part DLC for the game. Being the same characters but set in Rapture, one would expect that The Reveal would be the same as the base game. But no, because it's not the same characters. You're not playing as Booker, but as Comstock - himself an alternate universe version of Booker - and you (Comstock) fled to Rapture after accidentally killing a version of Elizabeth in the above mentioned Portal Cut. So Elizabeth - the version here, at least - is not your daughter, but the daughter of some alternate universe version of you. She's also here to kill you.
- Invoked by a minor character in Baldurs Gate 2. The player character overhears a conversation between a cleric and a woman claiming that the child accompanying her is theirs. She's halfway through demanding money to help raise the child when said child says they "like "this "daddy", revealing her trick. She later tries the same thing on the player character if they're male.
- In Fallout 4, the player eventually finds out that Shaun, the son they've been looking for is none other than the leader of the Institute, having been taken from cryogenic preservation 60 years before the player gets out and is now an old man.
- In Castlevania: Lords of Shadow – Mirror of Fate, Trevor loses the final battle with Dracula and is impaled by his own Combat Cross. As he lies dying, the Mirror of Fate shows him exactly how and why Gabriel Belmont became Dracula. With his last breath, he expresses pity for Dracula and calls him "father". Dracula is shocked by this and looks at the Mirror, which shows him his late wife Marie giving birth to Trevor and giving him to the Brotherhood to be raised in secrecy. Dracula, horrified that he had just mortally wounded his own son, forces the dying Trevor to drink some of his own blood in a desperate attempt to save him. An attempt that is only partly successful, since Trevor eventually rises as a vampire himself, Alucard.
- In Zero Time Dilemma, one ending of the game, the D-2 ending, has Sigma and Diana left alone in the bomb shelter for the rest of their lives. They manage to survive for about a year and have twins during that time, but when they run out of food to sustain them, they decide to use a time-traveling device they found to send at least a copy of their children through time to be able to live a more full life than starving to death with their parents. When Diana realizes in a separate timeline that one of those twins turns out to be Phi (regaining her memories via Mental Time Travel), she immediately breaks down into tears and hugs her. Oh, and the other twin ends up becoming Zero, the mastermind behind the game, which is a parentage Sigma and Diana are a bit less proud about.
- Darths & Droids inverts the classic scene, with Luke Skywalker being aware of the connection but Darth Vader being not, resulting in this trope. Still, a couple strips after that, Vader gets his own shocking twist in. Or rather, her own twist.
- The Order of the Stick: Elan's father may have spoofed Luke, I Am Your Father when he showed up in this strip, although it's a case of Luke, You Are My Father because Elan's father was introduced one strip before the reveal except for a flashback here, in which he wasn't named. Still, the "reveal" came as no surprise to someone with a good memory.
- The Inexplicable Adventures of Bob!: Jean is a bit insistent that all of the peanut butter monsters generated by her project are, in a sense, her children. Nonetheless, she seems freaked out every time she encounters one for the first time.
- In Niels & Gang, a young teenager shows up and claims to be Niels's child by a Danish woman he had an affair with as a teenager. Duncan is automatically suspicious of Niels Jr - with reason, as it turns out his name isn't Niels and he isn't exactly Niels's son. He's transgender and was born female; the name he was given at birth is never revealed, but Niels gives him a new name, Magnus, to avoid confusion.
- Last Res0rt: Veled tells White Noise that she is his daughter. At first, he doesn't believe it. A few pages later, he's properly convinced.
- In MYth: Distillation there's a variation. Zeus, being the dense dork he is, needed for Metis to reveal that the girl in his dreams is the result of their "embrace" on that night in Gaia's garden. Zeus, of course, freaked out.
Zeus: You...You mean she's my...?!
Athena: It's rude to point.
- Subverted in Ozy and Millie, Millie at one point enters a magical land through a Portal in Ozy's couch, and meets a fox kid named Locke who shows up from time to time throughout the series. It turns out that in this magical land everyone is born old and grows younger, and Locke when he was older came to Millie's world, and fell in love with her mother but went back home knowing that their relationship would never work as they are aging in opposite directions. But that was after he got her pregnant. Regardless, sadly once Millie tells him the truth, he's too immature to care nor fully grasp the situation.
- In Runescape Gods Exposed, Iban shows up in one episode saying Zamorak is his father. Judging by his response this has been going on for a looooong time.
- Gargoyles - when Goliath and crew arrive in Avalon, he discovers that the eggs that they managed to save from the clan massacre were brought there, hatched, and were all now young adults; one of whom is his (and Demona's) daughter, Angela. The comic later points out that Gabriel, Angela's friend on Avalon, is the son of the two Gargoyles that became Coldstone and Coldfire.
- Although this leads to awkward situations for Goliath and Angela. Gargoyles raise their children in a community with no child being the son or daughter of one specific parent. Angela, being raised primarily by humans, worries a lot about her parentage in comparison. Goliath eventually acknowledges his biological parentage to her, to her delight. She's less delighted about learning what kind of person her mother, Demona, is.
- Batman Beyond: Due to some... complicated DNA matters, Bruce Wayne is the biological father of both Terry and Matt McGinnis. And it wasn't Bruce's fault; Amanda Waller arranged it to ensure there would always be a Batman.
- Luke, I Am Your Father is parodied in Futurama Benders Game with Igner revealing to the professor he's his son, complete with ripped lines from Star Wars and a lightsaber duel.
- The Simpsons had an episode in which Mr. Burns's long-lost son turns up - voiced by (and drawn to look like) Rodney Dangerfield.
- Later on, Krusty's long-lost daughter shows up.
- Dermot from The Venture Bros.. Double Subversion: He believes himself to be the long lost son of Brock Samson. Turns out... he's actually Rusty's kid.
- In Young Justice, the exchange is completely non-verbal and takes about ten seconds. And it's a whammy, with Superboy revealing to Superman that he is his clone.
- Happens again in season 2 at the end of "Salvage" when Jade shows Roy their baby girl Lian.
- Happens yet again in "Bloodlines" when Bart announces that he's Barry and Iris' grandson from the future.
- The main reason that Eva from Ōban Star-Racers chases after Don Wei is because of this trope, although when she meets him, he doesn't recognise her and she takes up the name Molly instead. He works it out eventually.
- In the season 4 finale of Archer, Lana reveals that she conceived her daughter using a frozen sperm sample Archer donated after a cancer scare a couple seasons ago. Archer doesn't hear the explanation due to his tinnitus acting up, but he figures out the truth when his newborn daughter uses his trademark "shut up while I drink" finger gesture while nursing. As he "meeps" in shock, Lana introduces him to his daughter Abijean.
- Two examples in Moral Orel:
- Reverend Putty finds out that Stephanie is his daughter. Despite him still being a virgin at the time. It happened because Stephanie's mother was a Stalker with a Test Tube and stole his tissue full of his...ahem, leavings after A Date with Rosie Palms to impregnate herself with.
- Nurse Bendy is Joe's mother. This example's a tad complicated cause she remembers having him, sort of, but she had been forced by Joe's father to not acknowledge that they were related.