Why the men develop the nipples if from an evolutionary point of view they are of no use to them? In womenin fact, the nipple is essential for breastfeedbut in men apparently it’s no useThe presence of this anatomical feature in male individuals can be explained by going back to the embryonic development of human beings and to mechanisms of evolution. Both males and females originally correspond to a single embryo that during his early stages of development – therefore when the body begins to gradually take shape – it does not yet present obvious sexual differences: it is precisely in this period (between the fourth and sixth week) that the basic anatomical structures which characterize both sexes, including nipples. It is only later, around the seventh weekwhich activates the genes that lead to sexual differentiation (in particular a gene called SRY, present in the Y chromosome, characterizing the male sex). When this process is triggered, however, the development of the nipples has already begun and therefore the latter ultimately remain in men as well.
On the other hand, the question remains open: why, being a useless trait in male individuals, evolution has not led to theNipple Removalperhaps even in a later phase of embryonic development or even of the already formed individual? There is no 100% certain and unequivocal answer, but we probably have to refer to How natural selection works. Evolution tends to favor all those traits that confer a advantage in terms of survival and reproduction and to disfavor to the point of canceling out all those characteristics that instead lead to evident disadvantages. In the case of male nipples, their presence does not entail any significant disadvantages and, consequently, there has not been sufficient evolutionary pressure to make them disappear.
