" Not only do we look different from other apes, but each human sex also has distinctive body traits shaped by sexual selection. Men are taller and heavier on average than women, with more upper body strength, higher metabolic rates, more hair, deeper voices, and slightly larger brains. Some of these traits may have evolved for sexual competition against other males. But male bodies are also living evidence of the sexual choices made by ancestral females. Men grow beards, and possess penises that are much longer, thicker, and more flexible than those of other primates. These are more likely to reflect female choice than male competition. Women also evolved to incarnate male sexual preferences. Women have enlarged breasts and buttocks, narrower waists, and a greater orgasmic capacity than other apes. "

― Geoffrey Miller , The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature