Splitting this off from Absurdly Youthful Mother (see TRS Thread here)
The description of that trope does not mention this, but examples of this keep getting added, muddling the purpose of the Trope.
Going ahead and putting in the relevant examples from Absurdly Youthful Mother. Will need a better description as well. We will most likely put the image currently on that page on this new one, and find a new image for Absurdly Youthful Mother.
It can be firmly stated that most people are younger than their parents. Duh. In the land of fiction, though, it can get a bit more complicated. For example, you might be a time traveler and go back in time and meet your mother at a time when she was younger than you are now. Or you aren't a time traveler, but your mother is immortal and at least looks younger than you do. It can even be done via magic or just plain old Phlebotinum.
The main point to remember is that suddenly your parents look the same as you or younger, which is going to be a little awkward at family gatherings or when introducing your boyfriend to your dad.
[[folder:Time Travel, Magic, Bizarre Alien Biology or Immortality are involved]]
Anime and Manga
Tenchi Muyo! has several of these, perhaps most notably Washu being Ryoko's mother, despite the fact that Washu actually looks younger than Ryoko. In actuality, while Ryoko is merely a child at 7,000 or so, Washu is, depending on who you ask, either 20,000 or older than the universe. She cheats via magical scientific age modification.
RahXephon has Quon, Ayato's "mom", who has been kept in stasis. Making her the same age as he is, and about alf the age of his twin brother Itsuki (Ayato too was kept in a kind of stasis)
Their "official" ages in A's, most likely determined by physical appearance, are 8 for Vita, 19 for Signum and 22 for Shamal. Zafira seems to pose as the family dog.
In Higurashi no Naku Koro ni, it's revealed in the TIPS/ Rei OVA that Hanyuu, who looks about anywhere from 8-12, in fact had a daughter way back when. However, Hanyuu is an immortal Physical God, so that probably explains things. She still looks extremely young, so it might be a combination of this, and "Pregancy at a young age is implied or stated" above.
Actually, there's a new arc all about her story in the DS adaptation, and it's notable that her sprite there looks much older than she does during the rest of the story. It's possible that she appears as a young girl in order to get Rika to better relate with her.
The show makes it fairly clear that she was physically an adult when she was pregnant; at least most people figured that to be that case.
The way this one saw it, in spirit form, she simply was the same age as the Furude heir. Rika being ten-ish, that'd make Hanyuu ten-ish as well.
In Dragonball GT, Goku is de-aged to childhood as the result of the Dragonballs, making him approximately the same age as his granddaughter, 13-year-old Pan.
Moka's mother in Rosario + Vampire is well over 200, but looked like she was in her early twenties. Justified, since her species are said to be immortal. Her daughter really is 17, though.
Chao Lingshen in Mahou Sensei Negima! is Negi's descendant. The problem? She's about fifteen and he's ten. She says it works out because she's a time traveling martian!
In one Sandman volume it's remarked that Orpheus' mother doesn't seem old enough to be his mother. This is understandable, since she is Calliope, an immortal muse from Greek myth. Less understandable is that despite being the child of Dream of the Endless and Calliope, Orpheus seems to be aging normally for a human...
Cable is about twice the age of both his genetic parents, Scott Summers and Jean Grey. Additionally, his mother was a clone of Jean, who was only a couple of years old when he was born (it's complicated).
The Neon Genesis Evangelion web comic fanfic Aki-chan's Life (a slice of life/ illustrated epilogue to another, very well written, fanfic called The Second Try) has a somewhat... complicated example. Aki the daughter of Asuka and Shinji, conceived after the events of the third impact was born when her parents were about 16 or so. Pretty young to begin with. Four years pass, then everyone was swept back in time and her parents returned to the age they were in the anime (14) while she remained unchanged (she's a very precocious 4). They still remain loving, mature parents, but the awkwardness of the whole situation is... well you get the idea.
The Return, Sunshine comes across as one of these to Muggles due to the complicated nature of Succubae relationships (in purely chronological terms she could actually be younger than 2 of her kids).
The main character of New Amsterdam is 400 years old but looks 35 (the age at which he became immortal via magical means); he sometimes seeks advice from one of his still-living sons, who is a naturally-aging 65-year-old.
Takeru Sato, the lead actor of Kamen Rider Den-O, left the franchise after the TV series; so for future movies and spin-offs, they de-aged Ryotaro into an 11 or 12-year-old boy, making him younger than his grandson Kotaro who is around 18.
In Rentaghost, ghosts manifest as they age they were when they died. So Hubert Davenport's mother, who died in her twenties, looks much younger than her son, who died when he was much older (his late fifties or early sixties).
The Doctor Who Expanded Universe Eighth Doctor Adventures novels: the Eighth Doctor at one point mentions being a grandfather -- he appears to be in his mid-thirties at the time. His companion Fitz is a bit confused. He later adopts a young girl named Miranda, who ages rather normally, so he looks about forty (and claims to be thirty-six) when she's sixteen, which other characters see as slightly unusual. But after she leaves to have her own life and they're later reunited, several decades have passed since the last time they met, so she actually looks older than he does.
Mind you, when the Doctor's granddaughter was a regular, the Doc looked old enough to be her grandfather. Of course, ever-more-youthful regenerations bring this trope into play.
In the Tenth Doctor episode "The Doctor's Daughter", the Doctor becomes a Truly Single Parent against his will, resulting in a young woman who, being Younger than She Looks, appears about ten years younger than he does. Whereas he, of course, looks nearly ten centuries younger than he is.
In Torchwood, it is revealed that Jack has a daughter and a grandson. She mentions being upset that she looks older than him. (Actually, the actress playing her was born in 1968, while John Barrowman, who plays Jack, was born in 1967, but, still.)
It's now been revealed that River Song is Amy's daughter. Amy's in her early 20's while River is much older in all of their encounters.
Angel is, at first glance, an Absurdly Youthful Father to Connor, who appears to be eighteen while Angel appears to be in his late twenties. However, Connor was only born recently, and received a Plot-Relevant Age-Up. Also, Angel is actually over 240, and only appears to be in his twenties because he's a vampire.
In the Gilbert and Sullivan operetta Iolanthe, the hero Stephron is half-fairy. Fairies are unaging and Stephron has a hard time explaining to his beloved that these nubile women he is seen embracing are, in fact, his mother and his aunts, all of whom look younger than him.
I wouldn't say a word that could be reckoned as injurious But to find a mother younger than her son is very curious
Tsugumi in Ever17 doesn't look much older than her sixteen-year-old children, as she stopped aging at seventeen. You's mother is a more conventional really-young-looking parent... because her "daughter" is really a clone of herself that she had made when she was diagnosed with a terminal illness in her teens.
You might not suspect it, but Drowtales' Queen Diva is a great-great-great (times x) grandma and well over 1000 years old by the time the story starts. Additionally, her Fusion Dance, Ragini/Liriel, makes her look about 12 once she fully manifests.
In Homestuck, in every session of Sburb, it is predestined that the players will all really be paradox clonescreated by one of the players during that session. While this process isn't explicitly shown in the Trolls' session (though the end result is), in the kids' session, we see that John first created Nanna Egbert, Grandpa Harley, Bro Strider, and Mom Lalonde and then created the children themselves by combining this quartet pairwise, thereby making them essentially just a few minutes younger than their biological parents, whom in most cases were also their acting parents due to having been sent to different points in time. John, however, is quite a bit older than his "father", who is actually his half-brother. On top of that, if you consider creating the paradox clones to be a form of parenthood, this means that John is, at age 13, either a father of eight or a father of four and a grandfather of four, or both, depending on your perspective as to whether the second generation should be considered children as well or grandchildren. In short: Stable Time Loops and genetics should never mix.
Nina and Layla's mom in Eerie Cuties does not look like could have had 13 children. Justified in that she's a vampire. (Vampires can reproduce in this verse the same as humans.)
Five hats means that five tropers think it is ready to publish.
You are saying that you think this draft is ready to be published. That means the description is not ambiguous,
it doesn't duplicate an existing trope, there are at least three examples, and the title makes sense.
Is that what you meant to do?
You are saying this draft has a ready-to-publish hat it does not deserve and you are taking it back.