Cristian Andreu
Explorer
Which is part of why I'd prefer the mechanics divorced from biology. I don't want to truck in Granddad Lovecraft's Thanksgiving Rants, but I like the idea of belonging to a fantasy culture or inhuman heroic group. I think there are ways to get at fantasy culture or fantasy species that don't rely so much on defining what you are, at a biological level, and I'd prefer something like expanded backgrounds or better affiliation rules to designate that over "race."
Like, being a dwarf or a Cimmerian might define some of the things you learned early on in life, some of your friends and allies, maybe what you can initially do, but it's an additive thing that doesn't define what you are (like with ability scores). I mean sure, maybe my Cimmerian warlock isn't getting a lot of mileage out of that Athletics proficiency, but you just don't get to be 13 in Cimmeria without getting in a few brawls, and this is something that gives you an edge when you're compared to a pampered Hyperborean warlock. That, and all your barbarian friends, and your ability to use a sword without getting winded. That makes you "tough," but it's what you know and what you can do, not what you ARE, physically.
But it does make sense that there would be biological differences between the races of a typical D&D world. If nothing else, the physiology alone should account for some baseline characteristics. Even if there are no genes in a fantasy world and it is all just magic, being intrinsically more resilient to certain substances or having a noticeably different muscular development would result in marked differences.
I mean, there is a huge difference in the capacity to exert explosive force between a human and a gorilla, even if we choose the more extreme corner cases of very strong men and very weak gorillas; having a race of intelligent gorillas with a +X to STR would be very reasonable.