I kinda like JB with a more tomboyish look, when she gets dolled up that horseface is more apparent. Someone told me the theory of girls' rumps getting bigger, it means they like getting it ALOT and from the doggie position and used Mariah Carey as an example.
That must be an old farmers tale. The reason why their behind are larger, is that women store fat mainly in their butt and thighs, whereas men store fat in their stomach area. Thus you never see a man proportioned like that. Any women who does even moderate amounts of exercise will never see a belly either.