Testosterone is an important androgen hormone (also called the sex hormone) present in varying concentrations in both sexes. Males have approximately 15 times more testosterone after puberty than females. Male testosterone is produced in the testes and is responsible for deepening of the voice, libido, sperm production, body hair, and muscle growth. In women, testosterone is produced by the ovaries and adrenal glands and plays an important role in fertility, libido, and bone strength.