It is also fairly common for black men to have bigger, rounder butts than white and asian males, and again, latino men tend to come in a not so distant second place. The answer to this obviously lies in DNA. Black and Latino men tend to be genetically inclined to have larger penises and butts as opposed to caucasian and asian men. There are PLENTY of black and latino men with small penises and butts, and while not naturally inclined to be endowed in the penile and butt area as much as blacks and latinos, there are a decent amount of white and asian men who have large penises and butts. Africa is hot. Heat radiation has positive selection pressure in hot climates, negative selection pressure in cold ones.