As part of their reproductive systems, men have external genital organs called testicles (testes). These two oval-shaped organs reside in a pouch of skin (scrotum) that hangs below the abdomen and behind the penis. In addition to producing the sperm cells that are used in reproduction, the testicles secrete the male hormone testosterone. This hormone plays an important role in the development and maintenance of typical masculine physical characteristics.
During fetal development, testosterone is necessary to form male genital organs. During puberty, testosterone is essential for the development of secondary sexual characteristics, such as facial hair, greater muscle mass and a deeper voice. In adult males, testosterone maintains muscle mass and strength, fat distribution, bone mass, sperm production, sex drive and potency.
Treatment of male hypogonadism depends on the cause and may involve testosterone replacement therapy. Hypogonadism affects approximately one in 500 males.
Signs and Symptoms
The effects of male hypogonadism depend primarily on the stage of life at which they occur. They can occur during fetal development, puberty or adulthood. During each of these stages, the signs and symptoms are distinct.
The sex chromosomes X and Y — you receive an X from your mother and either an X or a Y from your father — determine whether the gonads in an embryo develop into ovaries (XX) or testicles (XY). If testicles form, the hormone testosterone is produced and male sex organs develop.
Production of too little hormone by the gonads during early fetal development may impair the growth or functions of the internal and external sex organs. This can cause a condition in which the sex of the child is not clear by external examination at birth (ambiguous genitalia).
Mental and emotional changes also can accompany hypogonadism. As testosterone decreases, some men may experience symptoms similar to those of menopause in women. These may include:
