The reason it's pretty much nonsense, though, is because the differences between ethnicities beyond physical appearance are ENTIRELY cultural. Black people and white people don't "feel" inherently different or have different personality traits based on genetics
.
A middle-class African American doctor living in the suburbs has far more in common with his middle-class white neighbours than he does with an LA gang member, for example. Rich Japanese kids sent to private schools in the UK or the US end up having much more in common with their classmates than they do with their parents. Etc. etc.
There are distinct, measurable differences between the brain chemistry of men and women. There are NO such differences between humans of different races. The inherent differences are purely in skin / hair etc. colour and a few other physical features.
Pretending otherwise is actually quite dangerous and is what leads to ideas of racial supremacy. The idea that one race is more intelligent than another, or stronger than another. The idea that people can be genetically predisposed to violence or criminality, regardless of how they are raised or how their life goes.