Why do white girls tend to have smaller butts than black and Hispanic girls?

Black and Hispanic people have more under-lying fat because of the color of their skin. However, genetics certainly have something to do with it and not all Blacks or Hispanic people have large butts.

Black women (and men) have a slightly different angle of the pelvis to the femur which gives them a slightly higher butt. Not sure that underlying fat has anything to do with skin color, since I have seen some pretty large white butts.

The color of a person's skin has absolutely nothing to do with the size of their butts. It is the extra weight some people carry around that gives them a big butt. I work with the public, and I see not just big butts but huge ones on people of every race under the sun. To say that Blacks and Hispanics have bigger butts than any other race is a rather racist remark. By the way, most of the ones I see are on white males.