Why does males have nipples

However, at about six to seven weeks of gestation, a gene on the Y chromosome induces changes that lead to the development of the testes, the organ that makes and stores sperm and produces testosterone , according to the book " Exploring the Biological Contributions to Human Health: Does Sex Matter? After the testes are formed, the male fetus begins producing testosterone at about nine weeks of gestation, changing the genetic activity of cells in the genitals and brain. But by then, those nipples aren't going anywhere.

Human development explains why males have nipples. But why do men keep this vestigial structure? A vestigial body part does not serve an evolutionary purpose. In women, the glands help lubricate the area and make the area softer for breastfeeding. In men, they help make nipples sensitive in a good way during sex.

Erogenous zones in us are very important. And so, it has been retained for those purposes. When [an embryo] starts, it comes standard, [so] men have it.

It's an important part of [our] little world. United States. Type keyword s to search. Today's Top Stories. How to Eat Like Chris Hemsworth. Can men lactate? As evolutionary theory progressed through another Darwin and beyond, biologists refined their understanding of its mechanisms.

Gould and Lewontin contend that other factors besides natural selection control the operation of evolution, one being simply the lack of selective pressure against a trait. Why would natural selection do away with a harmless circle of flesh?

In another paper , in , Gould addressed the nipple query specifically. There is, of course, a proximate explanation for the persistence of male nipples. Males and females do, in fact, start from the same genetic blueprint. Embryos, in their first weeks, develop structures with the potential to become either male or female sex organs.

Only later do sex-specific hormones begin to mold those structures into either a clitoris or a penis, either functioning mammary glands or unproductive male nipples. Nipples are also highly sensitive, and research shows that in men as well as women they respond to sexual stimulation.