The sex hormones are steroids that control sexual maturity and reproduction— androgens for male functions and estrogen and progesterone for female functions. They are produced mainly by the female ovaries and male testes, which are endocrine glands. Sex hormones are secreted throughout a person's life, but production greatly increases at puberty and normally decreases in old age.

Men's and women's bodies produce both male and female hormones, synthesizing them from cholesterol and intermediate compounds. For example, females produce androgens in the ovary and adrenal gland (also an endocrine gland), but almost all ovarian androgens are converted to estrogens. After menopause, a female's fat and skin cells convert androgens to estrogens. Males produce estrogen in three ways: converting testosterone in the testes, converting androgens in fat and skin cells, and synthesizing it in the adrenal glands. At puberty, the hypothalamus in the brain produces increased amounts...