Androgen (from Greek andro meaning male), also called androgenic hormone or testoid, is any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to  androgen receptors. This includes the activity of the primary male sex organs and development of male secondary sex characteristics. Androgens were first discovered in 1936. Androgens are also the original anabolic steroids and the precursor of all estrogens. The primary and most well-known androgen is testosterone. Dihydrotestosterone (DHT) and  androstenedione are less known generally, but are of equal importance in male development. DHT in the embryo life causes differentiation of penis, scrotum and prostate. Later in life DHT contributes to male balding, prostate growth and sebaceous gland activity. Although androgens are described as male sex hormones, both males and females have them to varying degrees, as is also true of estrogens.