Why Do Men Have Nipples If They Do Not Breastfeed?

Greetings and blessing,

Hashem created everything in a planned and "compact" manner. Until the sixth week, the embryo in the womb is bisexual. In other words, while in the mother's womb, the embryo is capable of developing into either female or male, since at the beginning it contains all the components necessary for creating both sexes (ultimately, the final gender of the newborn is determined by the number of chromosomes).

It would not be logical for a woman to carry two wombs inside her, one for a male embryo and one for a female embryo. Therefore, at the beginning of the process, the embryo carries components of both sexes; this is reflected in the nipples, which degenerate in a male embryo but continue to develop in a female embryo. Such a process also applies to the development of the reproductive organ of the embryo.

It is important to note that this design exists in all mammals and is not unique to humans. Male mice and male dogs also have nipples. This is simply the most compact way for the embryo's development, and in fact the only way in which the embryo can fold within itself the potential to develop into either a male or a female.

For exactly the same reason, humans have a navel (commonly known as a "belly button"), even though it has no use once they have long left their mother's womb and are no longer connected by the umbilical cord. Similarly, the nipples of males are remnants from their embryonic stage.

An interesting question I have heard in this context is whether the first human had nipples and a navel. On the one hand, one could say that the first human lacked nipples and a navel because he was not born as an embryo (for indeed, nipples and the navel are remnants of being embryos in our mother’s womb). His children, of course, were born with nipples and a navel due to the birth process which necessitates these remnants. On the other hand, there is also the possibility that Hashem initially created the first human in the form and appearance that would be given to all subsequent humans, and therefore he was created with nipples and the form of a navel. (As the Sages said, the first human was created as an adult and did not need to grow through childhood stages and was able to speak without learning the language in steps; similarly, the first human may have been created in his final form, as if already born and passed through the stages of embryonic development). Material worthy of thought.

With blessing,
Daniel Bels