Patchwork Kids

When you cross a male with a female, you expect to get a son or a daughter, not a hermaphrodite.

—Richard Dawkins, The Greatest Show On Earth

When writing Kid Fic, it's of course necessary to come up with an identity for the child. This can be an interesting and fun experience - different traits from the two parents are passed on in unique and sometimes unexpected ways (some genetic traits even skip a generation!), forming a new, wholly original person.

Of course, certain fans have seemed to miss out on this concept, and as such make children that simply resemble one, or both, of the parents, with no original or unexpected traits. This may carry over to things like hairstyle (and colour), personality traits, and talents.

Of course, even this is beyond the grasp of certain fans, and thusly they just begin mashing up traits of the two parents. Now this is where the trope comes into play: Say Alice and Bob just got their freak on, What's the little bundle of joy gonna look like? Like Alice? Bob? A randomly decided combination of both parents through a complex series of gene combinations? .... HEEEECK NO.

Thats no fun at all.

What about two-toned hair? Sure! Add in a different-colored eye from each parent! And why wouldn't Alice and Bob name their child Balice?

This is a very special form of You Fail Biology Forever and Lego Genetics. And even if you don't worry about that kind of thing, it's still about as unoriginal as a child character can get.

Compare Gender Equals Breed. Subtrope of All Genes Are Codominant.

Examples of Patchwork Kids include:

Anime and Manga

In Hanamaru Kindergarten, Sakura has blonde hair and her husband has brown hair; their daughter Anzu's hair is blonde in the front and brown in the back.
Bizarre canon example from Magical Girl Lyrical Nanoha: Vivio, adopted daughter of Fate and Nanoha, looks like a perfect mix of her mothers' features, especially the face. Her blond hair is darker than Fate. However her Mismatched Eyes are Red and green, while Nanoha is purple, which makes you wonder if Yuuno's design somewhat involved, EVEN darker blond hair and green eyes by the way.
- Not to mention the voice (no, not the voice).
From the creator of Naruto, Kishimoto confirmed that a child born between a Hyuga and a Uchiha would have a Sharingan in one eye, and a Byakugan in the other.

Fan Works

Kingdom Hearts fans have crafted Roxel, the child of the both very male Roxas and Axel. He has Roxas's and Axel's traits smashed together. During the year or so after Kingdom Hearts 2 came out, he was all over Deviant ART's front page; every other day you'd see fanart of him. There there are even cosplays of him.
Sonic the Hedgehog has numerous Sonic/Amy children who are part-blue, part-pink; if children worked this way in The Verse, there must have been SOME extensive pure-breeding program in place to keep most characters a single color!
Given that most Touhou characters already appear to be mashups of mythological elements and symbols and are defined by them, it's not surprising that most fan-conceived kids turn out like this.
- Possibly as a parody of this, it's reached a point where canon characters are being considered to be Patchwork Kids of other canon characters.
One particular fic in the Iron Man/Captain America fandom justifies this by making the child essentially a clone (or a highly engineered child).
Made patently absurd in Brawl in the Family, where Kirby's dream about his and Jigglypuff's marriage comes complete with kids, all of which are mishmashes of Kirby and Jigglypuff. Right down to the appetite, apparently.
Some Bolt fanfic has Bolttens spawning half-kitten, half-puppy offspring.
It's popular in X-Men fanfics for the mutants' future offspring to have powers that are a combination of their parents' (for instance, a child of Storm and Bishop absorbing energy to fuel his weather control). It's worth noting that there is no precedent for this in the comics. Most second-generation mutants either inherit one parent's powers, develop original ones, or none at all.
- Although at least Nocturne's powers - very similar to those of her father Nightcrawler- also extend to an attack called "hex bolts" (named in reference to her mother Scarlet Witch). The physical principle behind it still goes back to Nightcrawler's powers though.
- Ruby Summers, the possible future daughter of Scott Summers and Emma Frost, can transform into a diamond that looks red because of her optic blasts that actually look black. In most (non-616) realities where major marvel heroes have kids, their powers are combinations of their powers. For a very obvious example, reality-9811 (What If? v2 #114, What If? The Secret Wars never Ended) where EVERY child of two heroes or villains has a form of powers inherited from both parents. eg. Wasp + Human Torch = Firefly who shrinks, has wings, and flame powers; Hawkeye + She-Hulk = Mustang, who is green, strong and resilient, with inhuman archery skills.
Happens very often in Percy Jackson and The Olympians fanfiction. Example:
- "Holly Athena Jackson is the daughter of Percy and Annabeth. She has strawberry blonde ringlets and green eyes. In case you can't tell, she looks exactly like Annabeth only with Percy's eyes."
- ...and that's not even getting into all the Percy/Annabeth children with one gray eye and one green eye.
- ... and that's not even counting the absurd amount of children that have blonde hair with black streaks or green eyes with grey flecks.
In Finding Nemo fandom, Dory and Marlin often have "patchwork" offspring, i.e. a clownfish with blue stripes instead of black-and-white, or a blue fish with a few orange scales here and there.
Painfully common in Harry Potter fandom. One particularly cliched, Mary Sue-ish example: "Nami Weasley Potter, daughter of Harry and Ginny, is a very beautiful girl. She has black hair and one brown eye and one green eye. She is a famous supermodel."
- Because Nami is SUCH a common english name
- This troper has read more than one Draco/Harry M-Preg fic that ends in a blond-haired, green-eyed kid.
- This seems slightly justified in Harry Potter fanfic, because it happened with Harry himself, at least in appearance (he's repeatedly described as looking almost identical to his father, but with his mom's Green Eyes). But that didn't happen with anyone else. Not even the Weasleys. Arthur and Molly, being redheads, obviously have redhead children, but beyond that don't look like copies. And their children's children seem to be about half and half. (And magical skill seems utterly unrelated to genetics beyond 'Children of people with magic almost always have magic.' Harry didn't inherit his mother's skill in potion making.)
Sailor Moon. Oh dear god, Sailor Moon. If a kitten died every time a Patchwork Kid was born in Sailor Moon Fan Fiction, there wouldn't be any kittens left. One example is Hotaru and Chibiusa having a child with pink hair with black streaks and violet eyes with a hint of red.
Quite common in Tokyo Mew Mew fandom; There's a fic somewhere in the net where Kish and Ichigo have a half-human, half-alien baby. She had green hair with red streaks and amber eyes with brown flecks (Kish has green hair and amber eyes, Ichigo has red hair and brown eyes).
In Kim Possible fan fiction, when the parents are Kim and her rival Shego, having children with green skin and red hair, black hair with a red streak, plasma powers, or cutting out Kim's genetics altogether and making them clones of Shego is very common.
Cori Falls loves this trope. Jessie and James's kids are not only basically clones of their parents, but the youngest daughter has her mother's love of sweets and the son wants to be an artist like his father. Jessie herself is a mishmash of her mother and father in both looks and personality.
With Tengen Toppa Gurren Lagann, fans are very fond of giving Simon and Nia's child Nia's eyes. Fanart tends to make fans cry, since Simon and Nia never got a chance to have children.
Fans of the Super Smash Bros. series or Nintendo in general have done this with various pairings, most of them from male/male pairings. Here are various examples.
Happens in The Nightmare Before Christmas fandom quite a bit. These "skeledolls" are a mixture of ragdoll and skeleton and very rarely, if at all, male. Then again, if two undead people can reproduce successfully, why should the fans pay attention to the rest of the biological rules?
Patchwork kids are starting to pop up in the Monster Buster Club fandom.
- An example would be Anneliese and Jake, Cathy and Danny's children. Jake has brown hair and blue eyes while his sister, Anneliese, has brown hair and one blue eye and one green eye. And she has psychic powers.
In Naruto fandom, Naruto's children always have blond hair, Hinata & Nejis's children always have Blank White Eyes and Sakura's children are mostly Pink, especially if they're Sasuke's and the writer doesn't really like him.
- Well seeing as all the females he'd likely be paired with either have hair colors that don't exist in real life or blond hair themselves, it's reasonable to conclude that his kids would have blond hair just by assuming blond would be dominant over blue or pink hair just like it actually is with red. The real problem is with multiple kids, because Naruto is a carrier for the gene for red hair, so if we figure that red dominates fantastic hair colors, there should be some red haired kids in there. Now if you paired Naruto with Ten Ten, then it would be wrong. Also, it's canon that Byakugan is a dominant trait.
The Banjo-Kazooie fandom occasionally spawns offspring for the title two, who are a bear and a bird. The result? Half-bird, half-bear offspring (if they don't follow the Gender Equals Breed trope). However, to be honest, they'd be far from the weirdest things in their universe.
One inside joke in the Pokémon Diamond and Pearl fandom has it that Volkner is the Patchwork Kid of Cyrus and Cynthia (never mind that Volkner is around the same age as those two...).
Better Off Not Knowing averts this: Hakini is implied to mainly take after P'Li—inheriting the height and the firebending at very least—although something about Zaheer's mug shot (Word of God says it's the cheekbones) seems vaguely familiar to her. As her biological parents have (luckily for her) played no role in her life, it's unlikely that they were the ones to name her.

Film

Inverted in The Great Muppet Caper: In the story, Kermit and Fozzie are supposed to be twin brothers, amd we briefly see a photo of their Patchwork Father - a green-furred bear with Kermit's collar and pupils, and Fozzie's hat.

Literature

In the A Song of Ice and Fire books, Daenerys envisions a grown-up Rhaego (whose name alone is a combination of "Rhaegar" and "Drogo") as basically Khal Drogo with Targaryen hair and eyes.

Live Action TV

Late Night with Conan O'Brien had a recurring bit called "If They Mated", in which images of a celebrity couple were combined into Nightmare Fuel. (Often by the end of a segment, they would subvert this by putting ridiculous theoretical couples together and getting silly non-patchwork results—Conan himself plus Scooby-Doo‍'‍s Daphne, whom he claimed he had a crush on as a kid, resulted in SpongeBob SquarePants.)

Video Games

Another canon example is Harvest Moon: Animal Parade. Your children will be a mix of you and your spouse—they have your face and features, but your spouse's hair and eye color.
- Rune Factory Oceans, unlike all of its RF predecessors, does the same thing, likely because it was the first game not to utilize portraits.

Web Comics

In The Order of the Stick, Elan inherited his outlook (and alignment) from his mother and his love of the dramatic from his father. His Evil Twin Nale gets his outlook from his father and his love of the needlessly complicated from his mother. They both inherited their father's hairstyle and mother's hair colour.
- Pompey's a half-elf, although his parents aren't seen, he has one elf ear and one human ear. In his case, it's pure Rule of Funny.
Averted hard in Freefall. "Aww. Kids are so cute when they're still young enough to believe that all mammals have the same number of chromosomes."

Western Animation

In Shrek, Dragon and Donkey fall in love. Shrek 2 introduces their children, the dronkeys.
The title character of Humf is a purple furry thing. His parents are a red furry thing and a blue furry thing. Apparently, furry thing genes mix in the same way as paint.
In the SpongeBob SquarePants episode "Just One Bite", Squidward dreams that he marries a Krabby Patty (it makes sense in context). Their kid looks like a Krabby Patty with six tentacles.
On Gargoyles, Elisa explicitly notes that Angela looks like Demona, but with Goliath's skin and hair color. A few episodes later is revealed that she is, in fact, their biological daughter.
Kaeloo: In Quack-Quack's Imagine Spot, Kaeloo and Mr. Cat's potential offspring are orange, whiskered tadpoles.