Bill: Shut up, Ted.
Ted: Remember when she was a senior and we were freshmen?
Bill: Shut up, Ted!
Parents in fiction rarely look old enough to have children of the age shown. Sometimes this is because of a Teen Pregnancy, or Soap Opera Rapid Aging Syndrome, or some form of time travel or immortality. Sometimes, it's for a more mundane reason. The parents remarried, adopted, or gained custody of the suspiciously old child through other means that justify the age discrepancy. Basically, this trope occurs when a relatively young person (usually in their teens or early 20s) gets a Promotion to Parents over other characters who are about the same age as themselves.
- In Elfen Lied, Kohta and Yuka (both 18-19) are given custody of Mayu (~13) by her mother as she doesn't want her any more.
- Gintoki in Gintama who is in his 20s takes in Kagura who's about 14. Interestingly he fulfils many aspects of the Dad the Veteran trope.
- Lyrical Nanoha:
- Nanoha officially adopted the then 6-year old Vivio when she was just 19. One fan comic had fun with this small age difference by having Nanoha introduce Vivio to her parents with no prior information, causing her father Shiro to have a breakdown when he thought that she got Vivio the usual way at the tender age of 13.
- Taking this even further, as of Magical Girl Lyrical Nanoha Vivid, Vivio can transform into a teenager/young adult version of herself, which, coupled with Nanoha's own rather youthful looks, makes it appear as if they are virtually the same age.
- There's also Fate, who's the official guardian of Caro even though they only have a 9 year difference between them.note Caro admits during StrikerS that she tends to view her as more of a Cool Big Sis than a mother as a result. Erio would also count, but he's officially under the guardianship of the forty-something Lindy since he was rescued back when Fate was still too young to officially be his guardian. Fate goes on to become Vivio's other mother, as well as Lutecia's legal guardian for the time when her mother Megane was still in her coma.
- Averted with Subaru Nakajima who, while likely old enough to become Thoma's guardian in Force, despite being only six years older than he is, asks her father to take him in instead (presumably, she'd much rather be his sister).
- Depending on your definition of adoption, Hayate takes this to extremes. She has called the several hundred year old Wolkenritter her children ever since she was nine.
- Nanoha's own mother Momoko was an example in the original Triangle Heart 3: Sweet Songs Forever continuity. Kyouya (who was her stepson) and Miyuki (who was her niece) are 14 and 16 years younger than her respectively. Whether this is still the case in Lyrical Nanoha or if they're Nanoha's biological siblings is unknown.
- Eureka (14-16) of Eureka Seven has three adopted children, all orphans. She's the one who orphaned them, and she adopted them after realizing how horrible it was that she killed their parents. In the epilogue, all three children are adopted by Renton as well, who is also 16, as Maurice, Maeter, and Linck all are shown to have the last name Thurston. It is also implied that Renton and Eureka are married, at least legally.
- At age 15, Fraw Bow from Mobile Suit Gundam starts taking care of the orphans Kikka (4), Retsu (5) and Katz (8). Seven years later, we see them again in Mobile Suit Zeta Gundam: 22-year-old Fraw has married victorious Hayato and they have adopted the three kids, who are now 11 (Kikka), 12 (Retsu) and 15 (Katz, who even joins the cast as a regular).
- Mobile Suit Crossbone Gundam: In Steel Seven, it's shown that Tetenith's stepmother Europa is, at the most, maybe 10 years older than she is. Likely a case of political marriage on the part of her father Crux, who was the sovereign of Jupiter.
- Mobile Suit Victory Gundam: 12 year old Shakti rescues an orphaned baby after a Zanscare attack, and is still shown raising him at the end.
- In Sailor Moon, the Outer Senshi (all 16-17) adopt Hotaru after she has magically regressed to an infant. She then magically re-ages to around 13.
- In Sword Art Online, Kirito (age 16) and Asuna (age 17) adopt the little girl Yui in the VRMMORPG. Yui is technically less than two years old but acts closer to a precocious six year old.
- Yuuri (16), from Kyo Kara Maoh!, adopts the ten year old girl, Greta, who tried to kill him in her first appearance.
- Satoshi, from D.N.Angel, was adopted as a teenager by a man in his twenties.
- Beelzebub: Oga is made Baby Beel's foster father through a Deal with the Devil at age 15, while the foster mother Hilda is 16. However, virtually everyone else assumes that they are Type 1 teen parents.
- Bleach: Thanks to Abusive Parents, Sora Inoue kidnapped his sister Orihime when she was three years old and ran away from home. His act saved Orihime's life but left him Promoted to Parent at the age of eighteen.
- An erotic Korean manhwa aptly named My Stepmom (alternatively known as This Doesn't Feel Like Me) goes like this: A young male protagonist has a new stepmom who is barely 10 years older than him. She's kind and all... for the most part, except that she likes to dress provocatively and all but stated to develop sexual interest on the protagonist (who already has a girlfriend) and eventually did seduce him to have sexual encounter with her (several times). In a somewhat complicated twist, several flashbacks later reveal that she's the protagonist's sort-of stepsister, since she's actually the bastard (and abandoned) daughter of the protagonist's ex-stepmother with her previous partner before marrying the protagonist's father (ignoring that, the ex-stepmother really slept around a lot with many men before and after marrying the protagonist's father and the stepmom had her killed for abandoning her when she was little).
- You're Under Arrest!: Ken Nakajima's stepmother Sena, who is younger than her stepson. Played for Laughs when Miyuki and Natsumi at first think she is Ken's biological mother and try to figure out how it happened. A major plot point involves Sena trying to get Ken to acknowledge her as his mom.
- Miss Kobayashi's Dragon Maid: Kobayashi (25) takes in Kanna, who is officially about 16 years younger than her (though in reality, Kanna is probably several hundred years older than her).
- Played with regarding Evangeline in UQ Holder!. While she was born some time during the Hundred Year's War and normally looks like an adult, her true form is exactly ten years old (having been turned into a vampire on her birthday). This in contrast to her fourteen (actually two) year old adopted son Touta.
- Gon from Hunter × Hunter was raised by his father's cousin Mito. At the start of the series she's 24 to his 12, and she's had him since he was a toddler, meaning she couldn't have been older than 14 when Ging left him in her care.
- Jeff Foxworthy jokes about his father getting remarried to a woman young enough that Jeff has to take her to school the next day.
"Look both ways, Mom!"
- In the Age of Apocalypse, Rogue married Magneto and thereby became the adoptive mother of the sole survivor of his children, Quicksilver. He is an unspecified number of years older than her. (It could still happen in the main timeline).
- In the current adjectiveless X-Men series Jubilee finds and adopts an abandoned baby she names Shogo. This despite only being 17, and thanks to being turned into a vampire she'll be the same age even as her kid grows up.
- Robin: Tim's stepmom Dana is young enough to be his older sister, though there would be a significant age gap, and looks younger than her actual age. She is near Dick Grayson's age, and he would eventually become Tim's older brother through adoption.
- In Harry Potter fanfic If Them's the Rules, eighteen year old Harry adopts the eight year old Tom Riddle.
- There's a Touhou 4koma in a near-mundane setting in which Suwako and Sanae, who already have this kind of relationship in canon, are classmates of the 11-year old Letty and 17-year old Yuuka respectively (Usual warnings about Danbooru and NSFW ads apply). They are still mother and daughter, in that order, which has been commented on being a special case. It has been theorized that Suwako merely looks young... and also has the mentality of a child and still attends elementary school. It has eventually been shown that they both look their age and aren't related in blood, which does raise the question of what in her name Kanako was doing at a children's festival with a bag of sweets and a marriage contract.
- Child of the Storm has Jane Foster is in her late twenties when Harry is thirteen. This contributes to the initial awkwardness between the two, along with the Parent with New Paramour thing, even if Lily is long dead (and gently firm on the 'til death do us part bit, even if she's Not Quite Dead)), with Jane lampshading the relatively small age difference and noting that she doesn't think she's ready for kids yet, let alone a teenager. Over time, though, Harry becomes a Shipper on Deck for Thor/Jane and has a ready-made maternal substitute in his godmother Wanda, so Jane - who treats him more like her foster brother, who's maybe five years older than Harry (who sees her as a sort of Cool Aunt) - doesn't have to take that role.
- Stars From Home initially has Charles, who is around 30, remarking that he actually could be Scott's father... until they realize apparently-15-year-old Scott is actually 25.
- Subverted at the end of White Devil of the Moon. Lindy adopts Alicia, who was born the same year as her but spent close to 30 years in medical stasis (and thus didn't age past 5).
- In The Outside, Promotion to Parent aside, Satsuki is about 10 years older than Ryuuko and is very much on the same emotional level (if not a tad older) as she is. However, since she was about 13, she tries to fulfill a parental role for her sister but fails, as she doesn't have to many skills to care for herself, let alone her little sister, properly.
- In What Might Have Been, Amethyst has come to see Rose as something of a mother when it was explained to her what a "mom" was, even calling her "Mom" a few times.
- This is basically the situation for Dadvid and Momwen in the Camp Camp fandom, what with David and Gwen both being in their mid-20s and Max and Nikki (the two most common adoption cases) both being 10 and other possibilities (like Harrison and Nurf) only being slightly older (if that) or slightly younger (in the case of Dolph).
- Monsters University: Don, who has been the Older Sidekick to the rest of the Oozma Kappa frat boys, gets engaged to his frat brother Squishy's mother Sherri at the end of the movie. Everyone is weirded out (or it's at least made awkward by Don trying to make it not sound awkward) by the idea of their classmate and their other classmate's mother getting married while both classmates are still attending the same college and classes.
- Bill & Ted:
- From Bill & Ted's Excellent Adventure:
Ted: [whispering to Bill] Your stepmom's cute.
Bill: Shut up, Ted.
Ted: Remember when she was a senior and we were freshmen?
Bill: Shut up, Ted!
- During their report, while chatting with Sigmund Freud, Bill claims his only problem is "a minor Oedipal complex".
- Then in Bill & Ted's Bogus Journey, we find out that she divorced Bill's father... and married Ted's.
- From Bill & Ted's Excellent Adventure:
- Legally Blonde: Chutney and her stepmother, Brooke, are around the same age. This led to Chutney resenting/hating Brooke enough to want to kill her.
- Star Wars: Downplayed in the Prequel Trilogy. After Qui-Gon's death, Obi-Wan becomes Anakin's master and parental surrogate. At the time, Obi-Wan is 25 and Anakin is 9, making for a sixteen year gap. Qui-Gon, in comparison, was 48. As a result, Anakin and Obi-Wan have something between a brotherly relationship and a father-son one (Anakin admits he does think of him as a father figure, while Obi-Wan says he's like a brother), and they bicker like siblings as well.
- Paige of Women of the Otherworld adopted Savannah when Paige was 23 and Savannah was 13; the dynamics of this are explored when Paige narrates how she's young enough to remember pulling exactly the same crap Savannah's pulling, which gives her a certain edge in the inevitable parent-child negotiations. Then Paige marries Lucas Cortez, also in his mid-twenties, and Savannah has two parent figures less than a decade older than her.
- Twenty-five-year-old Kate Daniels becomes the legal guardian of twelve-year-old Julie. At first Kate refers to herself as a substitute mom, then as a crazy aunt, but she always refers to Julie as her kid.
- In the Flowers in the Attic series by VC Andrews, it's a significant plot point that Malcolm Foxworth fathered a child (Corrine) with his stepmother Alicia, who was sixteen when she married his father — a decade or more younger than Malcolm. He even states in front of his father that he cannot acknowledge a girl so much younger as his new "mother".
- In Randall Garrett's Lord Darcy stories, every story that Mary, Dowager Duchess of Cumberland is in also contains an explanation that she's a year younger than her stepson, the current Duke of Cumberland. She was his father's second wife, and it was a MayDecember Romance — she was in her 20's, he in his fifties when they married.
- In Adrian Mole: The Wilderness Years, Adrian's mother falls for and marries her lodger, who is around the same age as Adrian. The guy eventually leaves her and runs off with Adrian's own girlfriend.
- In The Hallowed Hunt, Ijada's father died, and her mother remarried. Then her mother died and her stepfather remarried. When Ijada explains this, Learned Hallana asks:
Hallana: And she's ah, how many years older than you?
- Twilight is a cross between this and Supernaturally Young Parent: officially, Carlisle and Esme are a twenty-something married couple with teenage foster children. In reality the whole family are vampires, all of whom are at least decades older than they seem—and in fact, Esme was actually born after her "son" Edward, despite biologically being about a decade older.
- At the end of the first Safehold book, Off Armageddon Reef, ten year old Hektor Aplyn becomes Hektor Aplyn-Ahrmahk, the adopted son of King, later Emperor, Cayleb, who is not even twenty yet. The adoption, and elevation to the rank of Duke of Darcos, are in of honor Cayleb's father, King Haarahld, who gave his life protecting Hektor, at the time mere midshipman on his flagship, in the Battle of Darcos Sound. Despite the small age gap, and the fact that his biological family is still alive and well, Hektor refers to Cayleb and his wife Sharleyan as "father" and "mother" when they're together. Hektor is generally shown early on to be far more overwhelemd by his new rank than his adopted parents.
- Star Wars Legends: A not-uncommon practice for the Mandalorians. They take parenting very seriously (to the point where calling one an "unfit parent" is a shoot-to-kill insult), but blood ties? Not so much. An adult with no family ties (or willing to sever former ties) who is willing and able to live the code, fight under Mandalore's banner, and accept training from an established Mandalorian is as good a candidate for adoption as an orphaned tyke who can be raised in the life.
- In Just Shoot Me!, Maya's father marries a woman who's exactly the same age as Maya. In fact, they used to go to school together.
- Super Sentai:
- After serving as the fake 18th head of the Shiba household, Samurai Sentai Shinkenger's Takeru is adopted into the family to become the actual 19th head in the finale. It's stated that the 17th head, Kaoru's father, died 17 years before, making the new adoptive mother 16-17 years old and younger than her son who, from his age in flashbacks, appears to be 6-8 years older than her.
- Ryouga in Bakuryuu Sentai Abaranger is 21 with parental responsibility for his orphaned 6-year-old niece.
- In Gosei Sentai Dairanger, 18-year-old Rin takes on the role of parent for 9-year-old Kou after the death of his mother. Played with in the show's Distant Finale which implies that they got married in the future.
- Kendall Casablancas of Veronica Mars, the gold-digging Trophy Wife of real estate mogul Dick Casablancas, has stepsons 7 and 9 years younger than she. She also sleeps with one of her stepsons' friends. And her oldest stepson, after his dad's large-scale fraud is exposed and is forced to flee the country, brings Kendall a bag full of new lingerie while telling her that she'll have to earn her upkeep "some other way" (though he could have been joking).
- Modern Family:
- Claire and Mitchell's stepmother Gloria is roughly the same age as them - it's stated at one point that Gloria is in fact a few months younger than Claire, and less than two years older than Mitchell. (In fact, Sofia Vergara, who plays Gloria, is two years younger than Julie Bowen, who plays Claire, and just over three years older than Jesse Tyler Ferguson, who plays Mitchell.)
- It's also been remarked on the show that Gloria's son Manny is technically a step-brother to Claire and Mitchell, even though he's the same age as Luke, his "nephew". Both Luke and Hayley have gotten around certain age limits by telling people "my uncle will be chaperoning" without mentioning which uncle. This usually backfires because Manny is actually a pretty good chaperone.
- In Defiance, Nolan doesn't look much older than his adopted Irathient daughter, Irisa. Their respective actors are about 10 years apart in age.
- In Series/ForçaDeUmDesejo Esther is just a couple of years older than her stepsons. Slave girl Luzia jokes that she's young enough to be Inácio's wife instead of his stepmother, which is an Accidental Truth as she was supposed to marry Inácio before tragedy hit them. Towards her other stepson Abelardo she settles more on a Cool Big Sis role.
- In Mad Men Roger Sterling leaves his wife for a girl barely older than his daughter, which creeps said daughter endlessly, and her stepmother's attempt to clumsily play the Cool Big Sis card (lavishing gifts on her and trying to give her advice on men) make it even worse. Bert Cooper refers to the second Mrs. Sterling as Roger's "child bride".
- In The Tudors, Princess Mary is actually older than her fourth stepmother Katherine Howard. In Real Life, she was just a couple of years younger than her fifth stepmother Katherine Parr.
- In Hollyoaks, Patrick Blake's girlfriend/later wife Maxine is the same age as his daughter Sienna. This leads to awkwardness when hospital staff don't believe Maxine is the step-grandmother of Sienna's own daughter.
- In Kamen Rider Ghost, protagonist Takeru is the heir to a Buddhist temple, whose head monk Onari became Takeru's caretaker when Takeru's father died ten years previously. At that time, Takeru would have been 8 years old and Onari 16, so this trope applies.
- In Zoo, Mitch's former stepmother Allison is about his age. He also holds a lot of resentment for her. It's later revealed that she used to be his girlfriend until his father seduced and married her. She later divorced him, when it became clear that monogamy is not his thing.
- This was the subject of the song "His Own Grandpa", a hit for Guy Lombardo in 1948.
- Ace Attorney:
- Trucy's dad Phoenix "Nick" Wright is 33, while she is 15. Protagonist Apollo does the math and is mind boggled by the implications of this fairly small age gap. However, it later turns out that Trucy was adopted by Phoenix (Of course, long-time players of the series could guess that already long before that point). This becomes somewhat Hilarious in Hindsight when you calculate the age difference between Apollo and his biological mother and learn that it is exactly the same as the age gap between Phoenix and Trucy.
- Ace Attorney Investigations 2 introduces another one, with Hakari Mikigami (Justine Courtney in the fan translation), age 26, and her adoptive son Shimon Aizawa (John Marsh), age 13. His biological mother and his adoptive mother were cousins. While the small age gap will clue the player in that he's probably adopted, the fact of importance to the plot is the name of his real father.
- In Final Fantasy VI, during the World of Ruin, Terra Branford ends up 'adopting' the orphaned children of a village where all the adults had died after the sundering of the world. When she rejoins the party, the two surviving teenagers Duane and Katerine, who are both last known to be sixteen in the World of Balance, help her take over caring for the children.
- In Princess Maker 2, you can be a very young man when you adopt your daughter (in fact, you can adopt her at 11, and she starts at 10...).
- In Tales of Symphonia, 12 year old Genis's sister, sole caretaker and mother figure is Raine, age 23. She's been raising him since infancy, making her roughly 11 or 12 when she had to start taking care of him because their mother abandoned them. It's implied in a Z-Skit that she's been a school teacher in Iselia for around six years, but it isn't clear what she did to support them before that.
- In Long Live the Queen, Bennett, the Earl-Consort of Dis, is only thirteen years older than his stepdaughter Gwenelle. He's been married to her mother Lieke since Gwenelle was a baby and she considers him her father.
- If Elodie plays her cards right, she can end up married to Ignatius, the older brother of the Duchess of Ursul. Elodie is 14 years old, 24 years younger than the 38-year old Ignatius, and a year younger than her own stepdaughter Briony (who is appropriately mortified).
- Both played straight and subverted in the van der Linde gang from Red Dead Redemption and its Prequel Red Dead Redemption II. Dutch van der Linde who was a Parental Substitute to John Marston, the Player Character, is only about fifteen years older than John whom he took in at twelve. In the latter that takes place twelve years earlier, he's also a father figure to its protagonist Arthur. He's only about six years older than Arthur whom he "adopted" when he was 15. However II introduces a co-leader/"co-parent" to John and Arthur with Dutch whose name is Hosea. He's about fifteen years older than Dutch which makes him thirty years older than John and twenty years older than Arthur (which isn't as common today but isn't that far off base in the 1890s). Hosea is also the person who's their actual Parental Substitute, Arthur even calls him his "pa" and says he loves him more than Dutch.
- If the female protagonist of Harvest Moon: Light of Hope marries Gorgan, she becomes the step-mother of Nova. Nova is not only the same age as the protagonist, but she can be married by the male protagonist.
- In Homestuck, Dave's much older brother is revealed to be his genetic father, through cloning shenanigans. The author indicated that Bro is 28 years old, so he had to have been about 15 when he adopted Dave. The same likely goes for Rose's mom, who is also quite youthful. Strangely, though the published version refers to Bro as "30-something". It may just be another case of Andrew Hussie being... well, Andrew Hussie.
- In Everyday Heroes, Thump Sharpley mentions that his mom is a year younger than he is. As his dad explains, Thump's biological mother died in childbirth; Dad later remarried a much younger woman.
- Following the events of chapter 50 of Drowtales, Ariel and Faen, who are the physical equivalent of mid to late teenagersnote , take over custody of Ariel's two youngest siblings, a toddler boy who's just learning to speak and an infant girl.
- Played With in that the children she cares for are her cousins and little sister but Bunny is in early to mid-twenties. Though she hasn't given birth to any children to speak of, but she is a bit young for motherhood. It is stated here that she didn't even finish college when Madgie came to live with her and is studying online so she can do so as to better provide for her youngest cousins. It was noted that, at some point, when Madgie was nine and she was twenty, she was mistaken for being Madgie's mother, something that would be virtually impossible, seeing as she is 11 years older than Madgie.
- Brittany's stepmother Ashley-Amber is about 10 years older than Brittany herself. Daria initially thought they were sisters.
Jane: How is it that she looks and acts exactly the same age as her own stepdaughter?
- Mr. DeMartino once (bitterly) mentioned his ex-friend marrying his mom, which presumably put this trope into effect.
- Brittany's stepmother Ashley-Amber is about 10 years older than Brittany herself. Daria initially thought they were sisters.
- King of the Hill has Hank's stepmother Didi, who was his classmate in kindergarten.
- Star Wars: The Clone Wars included an episode involving a clone deserter with young children. He's no older than 13 at this point while his children are about 5-6, but he's been fast-grown so physically he's in his mid-twenties, and the children are his step-children.
- Twilight and Spike's relationship varies Depending on the Writer in My Little Pony Friendship Is Magic, but Twilight is often treated as Spike's maternal substitute as she hatched and reared him. Their ages are vague but Spike is treated as a preteen while Twilight is implied to be in her late teens or early twenties.
- Jerrica from Jem is implied to be in her early-to-mid twenties yet a few of her foster daughters are in their mid-teens. Jerrica's father was their original foster parent, but Jerrica took over after his death. This is Truth in Television as Americans can foster at age twenty-one.
- Too many to even start listing them. Let's just say that the above Bill and Ted example is not even remotely far-fetched.
- Mary Queen of Scots and Elizabeth I used language like this in their diplomatic correspondence. Even though Elizabeth was only nine years older than Mary (and they were cousins to boot), Mary wanted Elizabeth to name her heir presumptive to the English throne and Elizabeth wanted Mary not to make any alliances with her enemies, so they made a big deal of being happy to love each other as mother and daughter... if each agreed to the others' terms.
- Henry VIII's marriages meant that Mary Tudor got this five times. The oldest of her stepmothers, Anne Boleyn, was about fourteen years older than her; the youngest, Catherine Howard, was several years younger.
- If a lord in Japan didn't have an heir or a daughter he would often adopt a grown man to be the heir.
- Robert Johnson was a friend and mentor to Robert Lockwood. Lockwood was four years younger than Johnson and was the son of Johnson's girlfriend, who was more than a decade older than Johnson.
- Before same-sex relationships gained legal recognition, it was not unheard of for one partner to formally adopt the other as an alternative method to legally identify each other as next of kin for purposes of taxation and keeping disapproving relatives under control. When a jurisdiction legalizes same-sex marriage, there are occasional stories of such couples trying to undo the "adoption" so they could get the marriage they wanted all along. This is still quite normal in Japan where same-sex marriages aren't legal.