Testosterone

This is the chemical that makes men, MEN. Just kidding....testosterone is a very important male sex hormone. Although it is considered a male sex hormone, women do have it, just in lesser quantities than men. As a fetus is developing, it is testosterone that promotes the growth of male sex organs and other male-specific features. It's also responsible for the male-specific changes that occur during puberty such as deepening in the voice and increased facial hair.