Editing Half-Elf (section)

==How they differ from real-life hybrids==
Half-elves rarely work the same way real life hybrid creatures do.<ref>But then, real life hybrid creatures don't always work the same way real life hybrid creatures do. You've got [[wikipedia:Category:Intergeneric_hybrids|hybrids from different genera]], [[wikipedia:Sturddlefish|hybrids from different families]], [[wikipedia:Canid hybrid|fertile hybrids]] and [[wikipedia:List of genetic hybrids|other such things]]. But there's no need to overcomplicate things yet.</ref> Some differences are well-known, others less so.

===Implications for how humans, elves, dwarves, etc. are related===
In real life, two species can only make a hybrid if they are still in the same Genus, the taxonomic level just above Species. This is why horses can have babies with donkeys, but not with dogs. In fact this is how we ''determine'' whether two species are in the same genus or not: if they can have ''grand''kids together, they're the same species, at most different subspecies; if they can have kids, but those kids are themselves infertile (more on that later), they're the same genus, but different species; if they can't have kids period, they're in different Genre and we'll have to do other, more time-consuming procedures to figure out how they're related (which is what we have to do from the get-go in the case of organisms that don't reproduce sexually, such as bacteria).

In most fantasy settings this isn't a problem, since elves, dwarves, halflings, gnomes, etc. usually look exactly as different as you'd expect another species in the ''Homo'' genus to look, however it also means that if humans and elves can have kids, then all other possible combinations should produce a kid as well.

That said, there's a little-known phenomenon that could be used as a partial workaround: Ring Species. A ring species is one that's ''in the process'' of diverging into multiple distinct species but isn't quite there yet, such that individuals of population A can have grandkids with those from B, B can have grandkids with C, but A cannot have grandkids with C. So it could work if dwarves were A, humans B, and elves C, but only for a setting where elves and dwarves are completely isolated from one another somehow; this arrangement would never arise in a setting where elves, humans, and dwarves are frequently found together in the same city.

===Infertility===
As mentioned earlier, two species can produce a child if they're in the same genus, but the child will themselves be infertile. The reason for this is a bit complex and has to do with the way genes are swapped around during the production of gametes. So you know how all your chromosomes come in pairs, one set from mom and one from dad? Well during the production of a gamete, each chromosome shuffles genes with it's partner at random (with the exception of the XY pair in men, for reasons we'll get to in a bit), which is the reason a married couple doesn't pop out the same baby every time the condom breaks. 

Now, if two organisms are genetically distinct enough to be different species, then their DNA has done enough mutation that a chromosome in one wouldn't be able to line up properly with the corresponding one from the other. So when their kid starts making gametes of their own, gene A gets swapped with a gene B instead of another gene A, resulting in the genetic equivalent of unreadably corrupted data (in the case of parents from different genre, the other chromosome doesn't even ''have'' gene A).

===Real hybrids come in pairs===
Something not well known by lay people is that Real-life types of hybrids actually come in pairs, depending on which species is the mom and which the dad. Mules, for example, only happen when the horse is the mom and the donkey the dad; if the horse is the dad you get what's called a hinny. So if elves existed in  real life, A human mom and an elf dad would produce something with entirely different stats than the child of an elf mom and a human dad.

So all in all, a setting with humans, elves, dwarves, and halflings would have 12, types of hybrids... which probably explain why nobody ever does it this way, now that we mention it.

===The second, non-biological possibility===

Tolkien directly stated that, as far as half-elves were concerned, the difference between human and elf was more a matter of divine patronage than genetics (which again weren't even fully understood yet at the time); since Half-Elves had claim to two possibilities of such patronage, and such patronage was usually exclusive, they needed to choose between them. The [[Dresden Files]] setting has something similar going on for Changelings (half-Fae).

In other words, in these settings, half-elf is (1) a purely transitory state; either they go fully human, or fully elf, and (2) a matter of belonging to two somewhat mutually exclusive groupings, a bit like how some people have [[wikipedia:Multiple citizenship|Dual Citizen status]].

===A third possibility===

The obvious third possibility is that "half-elf" is the game system's way of saying "midway between elf and human"; if you're more human than this, you get classed as "human", and if you're more elf, you get classed as "elf". The only system this editor knows of that almost pulls this off is Pathfinder 2e, where half-elf is just a sub-Ancestry/subrace of human, with the presumption that if a half-elf and an elf have a kid, it'll probably be classed as an Elf (it'd help if there was a "human blooded" Elf Heritage, but there are valid counter-arguments to that possibility).