What real differences do we know about? We cannot deny the existence of substantial average genetic differences across populations, not just in traits such as skin color, but also in bodily dimensions, the ability to efficiently digest starch or milk sugar, the ability to breathe easily at high altitudes, and susceptibility to particular diseases. These differences are just the beginning. I expect that the reason we don’t know about a much larger number of differences among human populations is that studies with adequate statistical power to detect them have not yet been carried
