 Following Aristotle, al-Fārābī explains the role of the reproductive faculty (al-Fārābī VC: 186–197) in the origin of the body and the soul. He holds that the female prepares the matter while the male prepares the form. Once again, he insists on the centrality of the heart, which provides the matter of the living being through the womb and the form through the organ that generates the semen. The semen, once entering the womb, finds inside of it the blood that had been previously prepared by the womb in order to receive the human form contained in the semen. The semen in turn endows this blood with a capacity that enables the blood to move and start forming the different organs that make up the human body. Hence, the blood from the womb serves as the matter that receives the human form contained in the semen, which is to say that the semen serves as the rennet by which the milk is curdled. Just as the rennet is that by virtue of which fresh milk curdles, while not being part of the curdled milk nor of its matter, so it happens with the semen, which is not part of the clogged blood or of its matter. Hence, the embryo is constituted in the same way that fresh milk is curdled by the action of the curdling principle, that is, the rennet.