Answer: First, in our period they have been finding evidence in archaeological digs that thousands of years ago people even did brain surgery.
In connection to the wisdom of Kabbalah, the Kabbalists know this not from our world. The Kabbalists were not involved with physiological research of women and men. They attained the higher characteristics of nature, of which we are the result. In this respect, the Kabbalists had absolute knowledge and could talk about the male and female body from a fundamental awareness.
For those who are beginning to study the wisdom of Kabbalah, it is not easy to connect our world immediately with the upper world, with the forces that manage us. The forces that create the human body shape its external state and internal organs, arranging them in their places, connecting between them, forcing them to function correctly, and after that, coupling men and women in order to give birth, to nurse, and so on.
All this happens under the influence of higher forces. When we attain the upper system, we no longer even need to learn what is happening in our world because we know precisely what is happening in it from an understanding of how the higher system organizes everything and brings it down into our world.
So in our world, we absolutely carry out the instructions of the upper forces, we have no possibility of operating otherwise. A Kabbalist who has a connection with the upper world sees what is happening at that height and immediately also knows what is happening in our world. It is no secret to him and not at all given to doubt.
From the Kabbalah Lesson in Russian 4/24/16