The primary hormone associated with the male sex is [[Testosterone]]. The primary hormone for the female sex is [[Estrogen]]. Biologically, these two molecules are eerily similar; in fact, if you take out a "rib" from [[Testosterone]], you will get [[Estrogen]]. Furthermore, all estrogen is synthesized from androgen, there is no other way for the human body to manufacture estrogen; it must always build an androgen, such as [[Testosterone]], and then take a piece out (the C-19 methyl group) through a process called [[aromatization]]. $\ce{C19H28O2 (Testosterone) ->[aromatase] C18H24O2 (Estradiol)}$ Testosterone:  Estrogen: