Sex hormone

Sex hormone, a chemical substance produced by a sex gland or other organ that has an effect on the sexual features of an organism. Similar to many other kinds of hormones, sex hormones may also be artificially synthesized.

Sex hormones known as androgens influence the growth and development of the male reproductive system. The predominant and most active androgen is testosterone, which is produced by the male testes. Testosterone is important at puberty and before, since its secretion by the fetal testis cells is responsible for the development of certain parts of the male genital apparatus. 

The female sex hormones, collectively called estrogens, are first secreted in quantity at puberty by cells in the ovary. They cause growth of the uterus, vagina, and breast; they act also on the bones of the hip, causing the specifically female widening.

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