Nipples, we all got them! Obviously, ladies need them to breastfeed babies. But why do guys have them? Are these to take up valuable chest space? More options for body piercing? To experience the special type of torture that is chafing while jogging? Or are they just there to feed hungry infants?
It turns out males have nipples because way back when we were tiny little embryos. We were actually girls. In our modern human body there are number of vestigial features like wisdom teeth that we don't need such as useless tail bones.
Male nipples are different. They aren't left over from some evolutionary event in the past—when males used to breastfeed. Nipples are artifacts of our own personal development. In the womb mammals go through a series of developmental stages.
Mammals grow from an eye-twinkle to a screaming infant.
The process goes something like this sequence;
- red-faced baby
Most babies are usually male or female. Girls with two X chromosomes and boys with an X and Y. Embryos start out following a female blueprint before our hormones get serious about sex. So, our nipples actually develop before our sex is determined.
Within the first several weeks. A pair of milk ridges is form on every embryo and thickening in the epidermis that runs from armpit to thigh. Eventually, these structure is pulled back to form two nipples.
Although, a surprising number of people mostly guys end up with an extra-supernumerary nipples. Somewhat, along the original milk-line even if they think it's probably just the mole. Again, these are NOT moles.
Shortly, after these nipples formed the baby get the Y chromosome. The Y chromosome is special sex determining gene that soon declares the embryo officially a male. Kick-starting the development of male hormones and eventually male anatomy.
Interestingly, not all male mammals have nipples. Let us check the mice for example.
In early embryonic development both males and females form mammary tissue. Yale University researchers found that a few days after that tissue starts to form. A special protein called PTHRP gets produced. This type of protein signaling different results in males and females.
In female mice, the protein stimulates those mammary buds to grow into nipples and all the requisite milk producing plumbing that comes with them.
But males it not only stops for their mammary development. It basically changes those cells into special receptors for the flood of male hormones. It also start circulating so the mammary cells don't just stop developing. They actually degenerate and when a male mouse is born he has no trace of nipples.
Of course, it all changes during puberty. When those estrogen waves start to stimulate mammary gland in breast tissue development in biosex females.
If male nipples are useless. Why do they have it? Uncoupling tends to happen only if there's a good reason for it in terms of reproductive success. Evolutionarily speaking female breasts are essential to the survival of the species and male nipples aren't.
In the end, male nipples are just a genetic byproduct of female breasts.
So, dudes are somehow exempted on nursing a baby. Which I think makes them unique and special.
How about you guys, do you something to say about nipples? Tell us on the comment box below.