You’ve just downed your fifth or sixth drink and are busy contemplating the many mysteries of life. Well don’t worry yourself too much – we’ve got the answer to one of them right here.
Humans are mammals, and so develop mammary glands that have the ability to produce milk that are used to suckle their young. Of course, we all know that it is females that do this, and so why females have nipples is quite obvious. But then why do males?
The answer is to do with the changes that occur during our early development as an embryo. For the first few weeks as the embryo develops, it follows a ‘female’ pattern. If the embryo is genetically male with a Y chromosome present, after six weeks it begins to develop the male characteristics, when a part of the Y chromosome called the SRY gene becomes activated. But nipples develop before this differentiation occurs – at about five and a half weeks. So even though the embryo becomes male, it is still left with nipples and some breast tissue.
So the next time someone tells you that men are from Mars and women are from Venus, remember that at one point in the womb we were all very similar. And I guess you boys will always have a little reminder of your feminine side.