This Is Why Men Have Nipples

Take a tour through just about any social media platform over the summer and you'll see people having fun in the sun. And a quick glance through the photos will show you the same thing over and over again: Men enjoying the day bare-chested while women's chests are always covered.

Flipping through any clothing catalog will show you the same thing. Mainstream TV shows, movies, even contemporary art all stick to the same rule. Few people seem to have a good reason as to why. What makes male nipples so different? And, for that matter, why do men even have nipples? After all, nipples are only biologically necessary for breastfeeding, according to Netter's Clinical Anatomy.

It turns out that men have nipples for the exact same reason women do: they developed in the womb before the fetus' sex was determined. Dr. John Launer laid it out in a 2010 publication through the Postgraduate Medical Journal.

"Men have nipples because embryos are always female in their early stages, and males only differentiate from the female prototype after a few weeks."

Same origins, different treatment

Put plainly, all nipples are the same until a fetus develops sex organs. What to Expect, one of America's most well-known pregnancy literature sources, says that this differentiation happens between seven and eight weeks after conception. At that point fetuses with a dominant XY chromosome pairing begin to develop testosterone, which alters the fetus' development.

All nipples start out the same, which makes the different treatment of male and female nipples all the more confusing. But the difference wasn't always so stark. Less than 100 years ago, men were banned from going shirtless as well. The Big Letdown, a book on America's treatment of nipples and breastfeeding, revealed that men's nipples were just as illegal as women's until 1936. 

Men won the right to go topless by flouting the laws of the time and going around without shirts in protest. Clark Gable even joined in and took his shirt off during It Happened One Night, the first time a man's bare chest appeared on-screen. Male nipples have since become common-place, something women today are still striving to achieve despite all of our nipples starting out the same way.