Sex Question Friday: Why Do Men Have Nipples?

A reader submitted the following question:

“Why do men have nipples? Do they have some purpose I don’t know about?”

Thanks for this great question! I’ve been asked about this many times before while teaching human sexuality classes to college students, so here’s what I tell them:

For the first six weeks that we’re in the womb, we exist in a gender neutral state, regardless of the chromosomes we carry. This means that each of us starts with the same set of bodily structures, which have the potential to develop toward either the male or female form depending upon what our genes and hormones direct them to do later on. It is during this neutral stage that the nipples begin to develop, which makes them a permanent structure that everyone is going to have for life, whether they are genetically male or female. The difference, of course, is that if you’re a genetic female, you will eventually develop breasts, whereas if you’re a genetic male, you won’t. For a closer look at how our bodies develop during the gender neutral stage and beyond, check out the short video below.

Scientists believe that the nipples begin developing so early because they play such a vital role in sustaining human life through breastfeeding. The male nipple is therefore thought to be nothing but a byproduct of the fact that biology so heavily favors development of nipples in women.

To answer the other part of your question, men’s nipples have no known reproductive or other function. That said, they do contain many nerve endings, which is why many men find that they enjoy having their nipples stimulated during sexual activity.

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Image Source: 123RF/Aaron Amat

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