Not at all true. I went to a super majority White HS with a bunch of girls with great asses and most of them were country girls who didn't listen to rap. I will always enjoy a chick with a great ass, even if her tits are small. 

 Here's the thing, if a girl has a healthy fat distribution, she will naturally have a bigger butt as she ages and has kids

Patrician choice is skinnier when younger then naturally larger with age