Estrone is one the three major hormones that are predominantly involved in the maintenance of the female reproductive system and secondary sexual characteristics. In women, the chemical substance is chiefly produced in the ovaries, but the testes of males also secrete small amounts of estrone and other estrogens. Estrone was first isolated in 1929 by Edward Adelbert Doisy, an American biochemist who later isolated estriol and estradiol as well. The significant achievements of Doisy have had a tremendous impact on modern society, since his isolation of the estrogens was a tremendous step toward the development of oral contraceptives.