The main gonads of the female are ovaries and in the male they are the testes (See fig. IV). These organs function as potent endocrine glands secreting hormones which make a man a male and a woman feminine. These hormones have profound influence not only on the sexual activities but also a number of body-organs and functions of an individual.
Estrogen and progesterone are the two major sex hormones, which are in large measure responsible for the characteristics that distinguish a woman from a man. The male sex hormones are androgen and testosterone. In both sexes, pituitary hormones play a profound role in controlling the functions of the sex glands.