The testes, located in the scrotum, produce and secrete testosterone. Although it plays a lesser role in their reproductive health, women's ovaries also create and secrete small amounts of testosterone. In both sexes, it is the hypothalamus and pituitary gland that determines how much testosterone is made.
Tiny amounts of this hormone are also secreted by the adrenal glands. Testosterone is the primary androgen in males, and increased levels of this hormone during puberty result in the development of facial hair, increased height and muscle mass, a deeper voice and an Adam's apple. Testosterone is also essential for the healthy development of the male reproductive system.