I think you're confusing races and species. There is very little genetic distinction between modern races, little enough that we wouldn't consider them separat

I think you're confusing races and species. There is very little genetic distinction between modern races, little enough that we wouldn't consider them separate subspecies in other animals, so neither do we in humans. This, combined with the fact that distantly related people are often grouped together (for example describing both Africans and Australian Aboriginals as 'black') is why race is often described as a social construct. There were in the past, however, different human-like species (we call them hominins). Neanderthals are the best-known of them. They were able to interbreed with humans, but apparently only with a very low success rate, hence we describe them as separate species.* This is similar to the way we describe horses and donkeys as separate species, despite the fact that they can very rarely produce fertile offspring[1]. All other species of hominin have since died out (it appears we outcompeted them as we moved into their territories), leaving only our species. *Some researchers, since they were marginally compatible, describe the different groups as subspecies rather than species. It's right on the line, and there's no obvious correct choice. [1] https://en.wikipedia.org/wiki/Mule#Fertility https://en.wikipedia.org/wiki/Mule#Fertility