Question: Why do men have nipples?

Sean Murphy answered on 22 Mar 2012:

As embryos, men and women have similar tissues and body parts. If anything the embryo follows a ‘female template’. That is why nipples are present in both sexes. It is the effect of the genes, the Y chromosome and the hormone testosterone that brings about the changes and gives the embryo male characteristics. Testosterone promotes the growth of the male sexual organs. Because nipples are there before this process begins the nipples stay!