The Mystery of Male Nipples and Adam’s Belly Button Explained

Yaniv asks: "Hello, if God created everything for a purpose, then why do men have nipples? Did the first man, Adam, have a navel?"

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Hello Yaniv, and thank you for your question.

Indeed, everything was created with a purpose, and with great wisdom. That wisdom is expressed in the fact that God designed everything in the most efficient and “compact” way possible. It would not make sense for a woman to carry two separate wombs in her body, one for a male fetus and one for a female fetus. Therefore, at the beginning of development, the fetus carries features of both sexes. For this reason, until the sixth week, the embryo in the womb is bi-potential, which means that it has the potential to develop into either female or male, because it carries within it the basic components for both. The sex of the child is determined later according to the chromosomes that shape development from the sixth week onward.

This compact biological design expresses itself, among other things, in the creation of nipples in the early embryo. In a male fetus, the nipples later atrophy, while in a female fetus they continue to develop. A similar process occurs with the development of the reproductive organs, which differentiate later depending on whether the child is male or female.

We can see this design not only in humans, but across all mammals. Male mice, dogs, and many other mammals also have nipples. It is simply the most efficient way for the embryo to hold within itself the potential to develop into either sex. For the very same reason, humans also have a navel (what children often call a “belly button”), even though it serves no purpose once the baby leaves the womb and no longer needs the umbilical cord. Just like the navel, male nipples are a remnant from early fetal development.

In answer to your second question, if Adam, the first man, had nipples or a navel: On one hand, we could argue that he did not, because he was not born from a mother’s womb as a fetus (since both nipples and the navel are remnants of our time in the womb). Adam’s children, however, certainly looked like us, because they were born naturally from both a father and a mother and developed as embryos.

On the other hand, we can suggest that God created Adam in the same outward form that would be given to all human beings after him — meaning he was created with the appearance of a navel. This explanation aligns with the teaching of the Sages: “Rabbi Yochanan said: Adam and Eve were created as if they were twenty years old” (Bereishit Rabbah, Chapter 14). In other words, Adam was created as a mature adult, fully formed, able to speak and function, without needing to grow from childhood. In that sense, it would be reasonable to assume that Adam was also created as if he had passed through all the natural stages of development, including the appearance of a navel and nipples.

It is, without a doubt, a fascinating idea.