Mama had a cow
Dad was proud,
He didn't care how!"
In works featuring Interspecies Romance, the characters sometimes manage to reproduce. In more "realistic" settings (including real-life), the offspring would be some sort of hybrid. In less realistic works, Gender Equals Breed might be in effect.
However... in certain works, the species of the child doesn't seem to have anything to do with the species of the parents whatsoever. This is most likely to occur in video games, works aimed towards a younger audience or basically any work where humor/symbolism/weirdness is favored over logic, but there are exceptions.
Examples where parents are the same species/breed still count if the child is not. The definition of "species" could be very liberal, but if the child's appearance or powers are explained by infidelity, adoption or shape-shifting in any form, it doesn't count.
Due to the trope's nature, a lot of artistic license is involved. More so for the Mythology entries which were made by ancient people before sufficient scientific understanding of how such things work.
When one (or both) of the parents don't like the desired outcome of this, see That Thing Is Not My Child!
Compare Hollywood Genetics. Contrast All Genes Are Codominant and Patchwork Kids, wherein offspring possess, respectively, abilities and physical attributes that are basically an extreme combination of both parents. Also see Either/Or Offspring, where the offspring of a different-species couple inherit one of the parents' species, and Dominant Species Genes, where offspring always inherit the same parent's species.
- The Netflix reboot of Aggretsuko provides a strange Implied example. Every onscreen couple that has children is same-species, with children to match. However, when Retsuko and Tadano discuss the prospect of having children, it's never brought up that he's a donkey and she's a red panda. It's weird considering the TBS version's propensity for biology gags.
- In One Piece:
- Part of the unique reproduction of Fishmen and Merfolk is this. Due to strong dormant genes inherited from their ancestors, Fishmen and Merfolk families can consist of different types of fish hybrids. A prime example of this is the royal Neptune family. The king is a giant-sized coelacanth merman, the queen is a normal-sized goldfish mermaid, their sons are normal-sized dogfish, oarfish, and sunfish mermen, and their daughter is a giant-sized smelt-whiting mermaid.
- Minks follow a similar reproduction rule, albeit with furry mammals instead.
- Thanks to their unique physiology based on the creatures the Queen eats, the offspring of a Chimera Ant Queen from Hunter × Hunter are Mix-and-Match Critters that are completely different from their mother. This is highlighted after the Queen prematurely gives birth to the new King and is in a critical condition. Despite some of her remaining offspring offering to donate their body parts to help her recover, they can't due to them and the Queen being completely different and incompatible organisms.
- One of the most "mature" settings would be the Marvel Universe, where mutants are technically the same species, but the appearance of a child (especially those with less human appearances like blue fur, tails, bird wings and so on) seems to have little to do with the appearance of a parent (not to mention their powers). One of the more consequential cases of this is Thanos of Titan, a mutant Eternal, whose very existence discredits the "current" in-universe "theory" of super-powered "mutants". He looks like a Deviant, which Eternals were created as foils too. And on that route, while Deviants can look like each other, they never look like their parents. This was done specifically to see if Deviants would still love their children (they don't).
- Rosalind and Rupert's son Gregor in Safe Havens is more of a human/plant hybrid than a human, thanks to some residual effects from Samantha's genetic research. Initially, it was thought he had daffodil DNA from the time Rosalind was stuck in a daffodil's body (long story), but recent events showed that he actually got Venus fly trap DNA from the time she and Rupert turned into them for some fun..
- The old Marvel UK anthology Marvel Bumper Comic had an Anthropomorphic Animal Adaptation of EastEnders called "Halibut Square". In this strip, Pauline Fowler was a chicken (mother hen and pun on "fowl"), Arthur Fowler was a mouse (meekness, as a [literal] Henpecked Husband), and their daughter Michelle was a snail (pun on "shell"). (Michelle's baby Vicki, however, is a snail/rat Patchwork Kid, despite which nobody knows who the father is.)
- Downplayed in RainbowDoubleDash's Lunaverse, where a pony foal will sometimes be of a different tribe than his parents. For example, Raindrops's parents are both pegasi, and so is she, but her little brother is a unicorn. Downplayed because the three pony tribes really aren't separate species.
- At the end of the short Team Fortress 2 fan film Spy and Pyro, the two of them give birth to a Spyro.
- Kung Fu Panda: Zigzagged in the first movie, where nobody seems to question that Po, a panda, is the son of a goose. Late in the first movie, Po's dad, after Po says sometimes he can't believe he's really his son, starts to tell him a secret which is teased to be that he's adopted, only to instead tell him the secret ingredient to his Secret Ingredient Soup. Then Double Subverted in the second movie where we find out Po's adopted.
Po: I just found out that my dad isn't really my dad.
Tigress: ...your dad?
Tigress: The goose.
[Po nods again]
Tigress: [no change of tone or expression whatsoever] ...That must have been quite a shock.
Po: Sheelishy realizing the obvious ...Yeah.
- The eponymous monsters in Scott Sigler's Nocturnal. They come in several varieties, but the soldier caste are typically superhuman monsters with inexplicably bestial features, given the appearance of 'Mommy,' her human 'grooms' and any potential 'Kings.'
- Possily the Firstborn from the October Daye series. Although they're all descended from at least one of three parents (Oberon, Maeve and Titania), each Firstborn produces their own different faerie race(s). When two Firstborn mate, they produce a different race altogether.
- In Arabian Nights, theres a story about two sisters who were jealous of their sister, who got to marry the Sultan. They asked to be her midwives whenever she gave birth, and whenever she gave birth they exchanged the baby with an animal and put the baby in a basket to send it downstream, pretending this happened every time.
- In the short story "It's a Good Life" Anthony's parents are normal humans but Anthony is some kind of undescribed monster. (In the adaptation on The Twilight Zone he looks normal, so that's not an example.)
- In Richard Matheson's short story "Born of Man and Woman", the protagonist is some sort of horrid abomination of a spider-mutant with multiple limbs, wall-climbing and a burning saliva. He was born to normal human parents who are disgusted by him and keep him locked in a basement.
- The original Stuart Little was a sapient mouse born to human parents, which was treated as more of a novelty than a freak incident. The movie changed this to Interspecies Adoption.
- In Lyn Abbey's Jerlayne, an elf mating with an elf will result in a random variety of fantasy beings including dwarves, banshees and dragons . The titular character's first child was a Rusalka. The only way to guarantee an elf being born is for a female elf to go to the human dimension and mate with a man who has some elf ancestry.
- Eddie Munster from The Munsters is the werewolf son of Herman and Lily Munster who are a Frankenstein's Monster and a vampire respectively.
- In the third season of Angel, the two vampires Darla and Angel produce a child that is just human and not demonic. Though in the show's mythology they shouldn't be able to have children at all, so it's Divine Intervention anyway.
- Norse Mythology:
- Both the Fenris Wolf and the Midgård Serpent are the offspring of Loki and female giant Angerboda.
- Loki's children also include Sleipnir, an eight-legged horse (with a stallion, Loki having shapeshifted into a mare).
- Classical Mythology: This happens all the time. For example, Gaea, the Earth, mated with Ouranos, the sky, at the beginning of the universe. Their first three sons were hundred-armed, fifty-headed humanoids; the next three were Cyclopes; and the last six were Titans. Why? Who knows?
- The offspring of the monstrous Typhon and Echidna are probably the best known creatures of this trope. To name a few, there is the three-headed dog Cerberus, the multi-headed Hydra, the Nemean Lion, the Erymantean Boar, the Chimera and many others.
- Echidna's own parents were Phorcys and Ceto, two gods who randomly had many bizarre or monstrous children, including Medusa, Euryale, and Stheno.
- Pegasus and his brother Chrysaor, who is sometimes depicted as either a giant or a winged boar, are the sons of the gorgon Medusa and the god Poseidon. The two of them were birthed when their mother was decapitated. Additionally, Chrysaor sired the three-headed Geryon with the naiad Callirrhoe.
- In The Odyssey, Odysseus meets Polyphemos, a Cyclops son of Poseidon. So Poseidon hooked up with a Cyclops? No; Polyphemos' mom was a sea-nymph named Thoosa, who may have looked like a mermaid. For some reason their kid was just giant and one-eyed.
- Egyptian Mythology has Osiris's family to note. Osiris's grandfather (or great grandfather depending on sources) Ra was a God that was depicted as a number of things. The most usual and famous is a hawk-headed man but others include a ram-headed man, a full ram, a beetle, a phoenix, and a serpent to name a few. Osiris's birth parents were Geb and Nut, the Earth God and Sky Goddess respectively. In some interpretations, Geb is depicted with the head of a snake or a goose, while Nut is depicted likewise in some interpretations as a cow. Osiris is overall human in appearance but his brother Set has the head of an desert animal which some speculate to be an aardvark. Osiris's son by his wife Isis is the falcon-headed Horus. In some interpretations, the dog-headed Anubis is also Osiris' son.
- The main family of the TV series Dinosaurs is a hodgepodge of dinosaur species yet they are all related by blood. Earl and Frances Sinclair are respectively a Megalosaurus and an Allosaurus with some Dilophosaurus features. Their two eldest children, Robbie and Charlene, are a Hypsilophodon and Protoceratops, respectively. Their third child Baby is supposed to be a Megalosaurus as stated by Earl, though in the episode "Out of the Frying Pan" he is depicted as a Ceratosaurus as an adult in Fran's Imagine Spot. As a sidenote also, Frances' mother, the elderly Ethyl Phillips, is an Edmontonia.
- The genetics of metatype are unpredictable. When two people of different metatypes reproduce, the offspring is most likely to be human, but could potentially be of either parent's metatype or a third type.
- In a parents-same, offspring-different example, about one in four daughters produced by pairs of giants (a troll subtype) will be born human.
- The original emergence of elves and dwarves by UGE (Unexplained Genetic Expression) was a mass occurrence of this trope, as human couples around the globe produced metahuman offspring.
- Dungeons & Dragons:
- In 1st Edition Advanced Dungeons & Dragons, the mating of orcs with ogres produces ogrillons: humanoids covered in bony nodules not found in either of their parent races.
- In the Forgotten Realms setting, hags are an all-female race who reproduce by raping human men. Only female children are hags; males are brutish hagspawn.
- The offspring of a half-Outsider (extraplanar being + mortal) and a mortal is called a Planetouched. There are about two dozen known types depending on the exact combination of parents.
- Hc Svnt Dracones:
- Vector species were designed to interbreed but to prevent homogenization they have "Mutt Reduction Protocols" built into their genes that usually cause the progeny of an interspecies couple to be one parents' species or the other, with a roughly equal chance of either. Though sometimes a grandparent's species pops up instead. And in very rare cases the Mutt Reduction fails and you get a sterile Hybrid.
- On the other hand Cog / Vector couples always have kids that are more like the mother, as it's simpler to translate what the father uses for "design codes" into what the mother uses than vice-versa.
- In Little Big Adventure 2, there is a family of three where one is a Grobo (antropomorphic elephant with giant head), one is a Rabbibunny (tall, thin, rabbit-like creature) and one is a Sphero (basically heads with short arms and legs).
- Bon Bonne in Mega Man Legends. While his apparently human sister and brother refers to him as their baby brother, he doesn't seem to have a single organic part. Granted, he could be a robot their parents built (thus making him their "brother"), but they seem to live in a world where no one ever makes any distinction between robots and humans whatsoever.
- In Viva Piñata, breeding two different Pinatas together can create a third type. For example, romancing a Rashberry with a Swanana will result in a Pigxie.
- Similarly, in Monster Rancher, this is the only way to get certain species. Some are justified though (like the offspring of a living cape and a stone slab with a face on it being a visible version of the invisible monster wearing the cape and living inside the stone slab).
- Pokémon: The vast majority of mons play by Gender Equals Breed and eggs are the same species as the mother. ... but then there's Manaphy. Manaphy is a One-Gender Race, and like other such mons, it can't breed with another Manaphy, only with Ditto. Unlike other one-gender races, the result is not another Manaphy, but Phione, which looks quite similar to Manaphy but never evolves.
- Garfield Thelonius Remmington III in Arcanum comes from pure human stock, but by some freak accident of birth he was born with an appearance indistinguishable from an orc. He makes his living working as a freakshow attraction, "Gar the World's Smartest Orc", impressing visitors with his knowledge of politics, mathematics and tea.
- In The Elder Scrolls series, the Khajiit are comprised of at least 17 known sub-species. The offspring of a Khajiiti pairing has nothing to do with the sub-species of its parents, but rather, the phases of the moon under which it is born. In a case of Hot Skitty-on-Wailord Action, these subspecies can range from the size of housecats, through various forms of humanoid cat-men, to elephant-sized tiger-men who can be ridden as Beasts Of Battle.
- In The Sims, when two occult Sims have a baby, their child will usually be one of the parent's occult types (for example, if a werewolf and a vampire have a baby, it will be either a werewolf or a vampire). In The Sims 4, however, it's possible for a non-vampire couple to have a vampire child if they give birth on a lot with the "On A Dark Ley Line" lot trait.
- RWBY: In supplementary materials, it's revealed that if two Faunus of different kinds mate, their offspring would be this. By comparison, Faunus-Faunus couples of the same species will always produce a Faunus whose traits are inherited from the Faunus parent. And a Faunus-human couple will produce either a human or a Faunus whose traits are inherited from the Faunus parent.
- Bill Holbrook's Kevin & Kell:
- The Wednesday 8 November 2006 strip has rabbit Danielle give birth to Francis with her fennec fox husband George attending. The infant born can't be identified offhand, though he later changes almost instantly into a human boy. This is a bit more understandable, since Danielle was a former human that crossed over to Domain, and that seems to be the reason Francis turned human. The implications are not lost on Lindesfarne, another former human.
- On the other side of the portal, and only on the supplementary Twitter, humans Catherine and Greg have a daughter who's a bear cub. Again, this is because Catherine originated from Domain, leading to her daughter becoming a Funny Animal. Oddly though, her animal DNA seems to come from her father: Catherine was a vulture, while Greg's counterpart in Domain is a bear.
- The Sunday 16 September 2012 strip of Mandy Seley's Curtailed has Mandy visit her parents. Mandy is a leopard, while her mother is a black housecat and her father is a bald eagle. Mandy's husband is a fox, who wonders if Mandy was adopted.
- In Vinci and Arty Vinci, a raccoon, eventually turned out to be the offspring of a couple of chihuahuas.
- In Neopets, some families in site events will all be the same species of pet, but others will have each individual as a different species. "Skeithnote plus Zafaranote = Ixinote " is a common joke among the fandom due to the revelation of the heritage of Sophie the Swamp Witch during the "Tale of Woe" arc. Whether the different-species children are implied to be Happily Adopted or produced organically depends on the writer It's also possible for some family members to start out as one species but then change to another, since there are several ways that magic/technology can transform pets into other species, including ones which players can use on their own pets (such as potions).
- SCP Foundation: SCP-166 is a humanoid with abilities similar to a succubus. Her mother was a nature goddess. Her father is Dr. Clef, a man with a Multiple Choice Backstory, who may or may not be entirely human, and has claimed to be the devil.
- The basic premise of Cow and Chicken is that a human couple somehow have a cow and chicken as kids.
- Mr. and Mrs. Cake from My Little Pony: Friendship Is Magic are two Earth Ponies, but their children are a Pegasus and a Unicorn. According to Mr. Cake, they're like that because they inherited traits from distant Pegasus and Unicorn relatives from both sides of the family...though he seems a little uncertain in saying so. And one of those relatives is only related by marriage, not by blood.
- In Blue's Clues, Mr. Salt and Mrs. Pepper are, respectively, talking salt and pepper shakers. Their children are Paprika, a spice container, and Cinnamon, a cinnamon shaker. This goes further in the reboot Blue's Clues & You!, wherein the couple have new twins - Sage and Ginger, miniature color-codednote corked bottles.
- On The Cleveland Show, Tim the Bear's parents were actually a black bear and a kangaroo, even though he displays no particular kangaroo qualities other than having brown fur. This is pretty much just mentioned for a gag.
- Subverted, but discussed in the SpongeBob SquarePants episode "Rock-a-Bye Bivalve" wherein SpongeBob and Patrick adopt a clam. Some onlookers not knowing that SpongeBob and Patrick simply adopted the clam and are just wearing wife and husband clothes, question how a sponge and a starfish could produce a clam offspring.
- On Rocko's Modern Life, this is combined with Lamarck Was Right. Dr. Hutchison, a female cat, marries Filburt, a male turtle, and lays an egg. Heffer, a steer, sits on the egg for Filburt. The result is two male turtles, one female cat. and a male steer.
- Discussed in The Simpsons, "Eight Misbehavin'", where an Adam Westing Butch Patrick (Eddie Munster) guest stars while Apu has some minor Actor/Role Confusion.
Apu: Hey, one question, Eddie.
Butch Patrick: Butch.
Apu: Yeah, right, right. If your mother was a vampire and your father was a Frankenstein [sic], how come you are a werewolf?
Butch Patrick: Huh, I never thought of that. Doesn't make sense, does it?
- The Imperial Family in Kung Fu Panda: Legends of Awesomeness includes a pig (Mei Li), a water buffalo (Lu Kang), and geese (Zu Chanhua and her son Zan). No further information has been offered.
- In the original Danger Mouse, Professor Heinz Squawkencluck was a mole and Dr. Augustus P. Crumhorn III was a wolf. In The Remake, there's a Professor Squawkencluck who's a chicken (and specifically stated in the background material to be Heinz's niece) and Augustus P. Crumhorn IV, who's a doberman (and has a daughter who's a poodle).
- OK K.O.! Let's Be Heroes: Enid's mother and father are a vampire and werewolf, respectively. Her twin brothers are a Frankenstein's Monster and Pumpkin Person. Enid is a witch, though she gave up practicing magic to become a ninja.
- In Yin Yang Yo!, a dragon named Edna manages to have two insects for sons: a cockroach named Carl and an ant named Herman. And in the finale, Master Yo, a panda, turns out to be Yin and Yang's father despite their being rabbits.
- The Bagel and Becky Show: Bagel and Becky are cat and dog siblings with a human mother.