Why do straight men devote so much headspace to those big, bulbous bags of fat drooping from women’s chests? Scientists have never satisfactorily explained men’s curious breast fixation, but theorists are gonna theorize. So let’s take a tour of the sexy speculation surrounding the human bosom — with a few stops to explain why it’s so hard to figure out just why breasts hold such allure.
Mammary glands are a defining feature of mammals, but humans seem unique in granting mammaries a large sexual role. That’s not to say interest in nipples is entirely unheard of elsewhere in the animal kingdom: In the book “Biological Exuberance: Animal Homosexuality and Natural Diversity” (Stonewall Inn Editions, 1999), Canadian biologist Bruce Bagemihl notes that a couple of primate species, including humanity’s close relative the bonobo, have been seen stimulating their own nipples while masturbating. Still, few mammals other than humans mate face-to-face (the behavior makes headlines when seen in the wild), so nipple stimulation isn’t generally part of the script.