The shape of the buttock is very different between males and females. The shape of men's butts is inherently different than women's. This is due to many factors, including skeletal frame, muscle mass, fat distribution, and the fact that you won't find a male's butt that's identical to a women's. Hormones are responsible for larger butts in women than in men. Hormones are a key factor in the distribution of body fat. The hormones of each gender determine which part of the body has more fat.