How does interbreeding work in your campaign?

[Pentius]

In the real world, different species cannot interbreed, this is true. But the existence of half-elves, half-orcs and Muls gives precedent to interbreeding, even to true-breeding offspring. This calls into question whether the difference species of humanoid really are different species, as is often thought, or if they are merely sub-species of the same specie. Such genetic diversity is not wholly unbelievable when one first considers the Toba Castastrophe Theory and the implications it has for how similar humans all are to each other in our world. Contrast the minor variations in human genes with dogs, which have what would appear to be a wide number of different species, but generally all create fertile offspring with one another at the end of the day.

How this works in game is a bit of a different matter. I'm more or less open to letting a player have any genealogy they want, so long as they don't mind at least briefly touching on how a half-human/quarter-drow/eighth-elf/eight-eladrin came to be. What I am generally not interested in is figuring out custom racial stats depending on which FR elven subrace your father was. I'll just ask a player to pick a 'close enough' race and use their stats.

Not that this really comes up too often.

 

[Jack Daniel]

In my campaigns, it varies greatly by the race or species in question.

Anything that isn't to some degree magical can't naturally interbreed outside of its species. When creatures are indeed magical, they can interbreed, but they can't usually hybridize.

Things which are magical -- demi-humans and goblinoids, dragons and extraplanars -- can easily conceive fertile offspring with each other or with humans, but these races nearly always breed true. That is to say, the child of two races will almost always belong to only one or the other of the parents' races, never a blend or a hybrid. In the case of wildly inhuman but very magical beings (e.g. dragons), it's a result of the innately enchanted nature of the magical being. For demi-humans and goblins, it's because these species are already genetically human anyway; they're just under a powerful, permanent, hereditary enchantment, and the offspring cannot exhibit the phenotype of two such enchantments at the same time.

Hence, the child of (say) and elf or a dwarf will be either an elf or a dwarf. The child of a gold dragon and a halfling will be either a gold dragon or a halfling. The child of a human and a centaur will be either a human or a centaur (just like in the Xena TV series).

Two exceptions to this rule are half-orcs and changelings. Half-orcs are a scrawny, sneaky, innately evil, contemptible, degenerate blend of human and orc, created by dark sorcery when a certain Evil Power decided that he wanted a breed of goblin that could pass for human at a glance and withstand sunlight. Plus, bonus, magically breeding half-orcs back with normal orcs/goblins gave rise to hobgoblins/uruks.

Changelings, meanwhile, are the relatively rare (1%) result of a pairing between a human and a demi-human or fae being. Instead of being fully human or fully demi-human, the child will on these rare occasions be a human that exhibits fairy-like (and frankly elvish) traits. Some misinformed individuals have been known to call these hybrids "half-elves," but changelings consider that appellation and insult, especially when their non-human parent isn't an elf.

 

[Aeolius]

This alone is why the TMNT RPG sold every copy.

Who needs turtles, when one has hags?

 

[Dausuul]

Why? Because members of different species cannot produce children with each other on their own. How many games do we have where all the other species, plants, animals, you name it, in the milieu can all interbreed to produce hybrids? What's a cat-dog combination? What's a horse-pig combination? What's a giraffe-hippo combination? Elephant-mouse? Kudzu-poison ivy? Beholder-hamster? Green slime-pigeon (look out!). It's laughable.

HEE-HAW!

<---- The donkeyhorse's response to this laughable proposition.

 

[TwoSix]

It only works in my campaign with copious amounts of Barry White.

 

[chaochou]

Deep gnome + rock gnome = A glam-rock gnome
Gnome + dwarf = A mawforged (the n-chromasome is lost)
Half-elf + half-orc = A half-fork
Halfling + human = A hum
Hobgoblin + human = A ho-hum
Bugbear + hobgoblin = A bearhug
Duergar + dwarf = Dwarfguarder (male) or Shergar (female)
Drow + high elf = A two-headed high drow
Lightfoot halfling + deep halfling = A halfling delight

 

[(Psi)SeveredHead]

Well I start with D&D.
For it seems a bit odd that only half-orcs, half-orcs, half-ogres and very few half-breeds are in the core rules. I'm not talking about 3rd party material.

For some reason orc/ogre-hybrids are well thought out, but otherwise I'm left with several questions.
Deep gnome/rock gnome?
Gnome/dwarf?
Half-elf/half-orc?
Halfling/human?
Hobgoblin/human?
Bugbear/hobgoblin?
Duergar/dwarf?
Drow/high elf?
Lightfoot halfling/deep halfling?

First of all, I think you're demonstrating that there are too many subraces here. I don't know (or care) what the difference between a deep gnome and a rock gnome is. A svirfneblin is just a "gnome, deep" on an index card as far as I'm concerned.

(And I just cannot picture a medium and small creature making offspring without plenty of squick. So no gnome/dwarf crosses. Although allegedly that's exactly what a gully dwarf is.)

Second, as a direct result of horny dragons in 3.x ("I'm JFK Dragon, and I'm here to sleep with your wife") I don't create hybrid combos that don't already exist in that particular setting. For instance, a half-tarek (a human/tarek cross) and muls (human/dwarf crosses) exist on Dark Sun, but the former don't exist anywhere else, and I don't expect to see the latter on, say, Oerth.

still I wonder what races should be able to interbreed and what shouldn't? Should you also limit the number of half-breeds or get "out of control"?

It's up to you. Are all these races just branches off a main path? In which case, presumably they can all breed with each other, but having viable offspring is quite another story.

In one campaign I was in, elves and humans could breed, but hadn't in hundreds of years because one particularly powerful (and mad) half-elf mage pretty much destroyed a big chunk of civilization. Each race blamed the other. Apparently no relationships had been founded since then. (We butchered one such couple due to a misunderstanding, literally killing a piece of the setting's history-in-the-making.)

 

[Smoss]

In my campaign world and RPG setting they don't. At all. Different species entirely, no fertility between them (Besides, I tried to make the other races as "not human" as possible). There are some magical alterations involving other races into humans, but nothing too major. Feel free to check out my design blogs for more info if y'all so desire.

EN World: Your Daily RPG Magazine - Smoss

Smoss

 

[RainOfSteel]

Who needs turtles, when one has hags?

That chart gets tucked away. Thanks. It'll be very useful for running standard games.

I can't actually give you more XP yet.

 

[Starman]

Midnight from FFG has dwarrow (dwarf/gnome), dworg (dwarf/orc), and elfling (elf/halfling) crossbreeds. There are no human/orc or human/elf races.