Why do men have nipples?

The nipples develop before the sexual characteristics of the embryo develop. Male nipples may not play an evolutionary role, but they’re not useless either: for some, nipples are involved in sexual arousal.

Male nipples exist because nipples begin to develop in all embryos before sexual differentiation occurs in the uterus.

Sexual differentiation is the process by which cells in an embryo take on specific functions and male or female characteristics begin to develop according to the embryo’s genetic instructions. While the nipples begin to develop around the 6th week, sexual differentiation occurs around the 7th week.

The changes that begin in males around week 7 occur due to activation of the SRY gene, also known as the sex determination gene. This activation will ultimately lead to the development of the male reproductive organs. During this time, the cells that have already formed the first nipples remain intact and fully develop in both men and women.

Male nipples are not designed for breastfeeding or breastfeeding. However, male nipples are used for sexual arousalwhich some experts believe may have an evolutionary purpose. Men have a dense reserve of nerves in their nipples that can stimulate sexual arousal, which, in turn, can encourage them to have intimate relations and reproduce.

Until puberty, male and female nipples are generally similar. When puberty arrives, the nipples undergo distinct changes. Female nipples begin to enlarge while male nipples, although growing, generally do not undergo as many changes.

Several conditions can affect male nipples, due to genetics, hormonal imbalances or other factors. They include:

• Gynecomastia: When there is an imbalance between the hormones testosterone and estrogen, men can develop gynecomastia, or enlarged breast tissue. It can affect one or both breasts. Medications, drug use, and health conditions can also contribute to gynecomastia.
• Galactorrhea: This condition occurs when milk or milk-like discharge leaks from a man’s nipples. Although sometimes harmless, this condition can develop due to side effects of medications or pituitary gland disorders that increase the body’s levels of prolactin, the hormone that stimulates milk production.
• Male breast cancer: Rarely, men can develop breast cancer. About 1% of diagnosed breast cancers occur in men. Cancer can cause a lump or thickening of breast tissue near the nipple. Other signs include inverted nipples, nipple discharge, or changes in the skin surrounding the nipple.