Pubescent boys go crazy for them. Adult men go crazy for them. Women are supposed to keep them covered up, despite many states making it legal for a woman to be topless anywhere a man is legally allowed to be. Yes, breasts are definitely a thing—but have you ever noticed that humans are the only ones with, generally speaking, permanently enlarged breasts?
Why humans have enlarged breasts, when other primates don't, is still a mystery. In non-human primates, enlarged breasts are a clear indicator that a mother is suckling young, while full breasts on a human are not even a positive indicator of fertility. It could just be a matter of sex appeal. Male ancestors liked plump, symmetrical breasts, so evolution selected for them.
Not everyone buys this reasoning, though, as some believe the human breast is the result of evolution pertaining to lactation. Florence Williams, author of Breasts: A Natural and Unnatural History, believes that big boobs are probably a result of natural selection pertaining to both male sexual preference and ease of lactation, telling Salon, "There's no doubt at all that a lot of men are really, really attracted to breasts! But it could be that that attraction came later or was secondary, and it's never really been satisfactorily proven that all men in all cultures across all times are obsessed with breasts."
Whether they're big because of survival, sexual preference, or both, the human female breasts remain to all of us—like a 12-year-old rummaging through the attic for his uncle's Playboy stash—a confounding mystery.
