If you're truly open to it, essentially it boils down to the fact that homo sapiens are our overall main species but homo sapiens had sex with other species, mainly neanderthals and another 1 or 2 other species that are now extinct. Some races of humans have larger traces of these ancestral species that differentiate us from pure homo sapiens. So technically, at a genetic level, there are in fact genetic differences such that differences between humans can be attributed to mixture of different ancestral species mixing and not entirely culturally related.