Definition of Hypogonadism:

Hypogonadism is when the sex glands produce little or no hormones. In men, these glands (gonads) are the testes; in women, they are the ovaries.

Causes, incidence, and risk factors:

The cause of hypogonadism may be "primary" or "central." In primary hypogonadism, the ovaries or testes themselves do not function properly. Some causes of primary hypogonadism include:

• Surgery
• Radiation
• Genetic and developmental disorders
• Liver and kidney disease
• Infection
• Certain autoimmune disorders

The most common genetic disorders that cause primary hypogonadism are Turner syndrome (in women) and Klinefelter syndrome (in men).

In central hypogonadism, the centers in the brain that control the gonads (hypothalamus and pituitary) do not function properly. Some causes of central hypogonadism include

• Tumors
• Surgery
• Radiation
• Infections
• Trauma
• Bleeding
• Genetic problems
• Nutritional deficiencies
• Iron excess (hemochromatosis)

A genetic cause of central hypogonadism that also produces an inability to smell is Kallmann syndrome (males). The most common tumors affecting the pituitary area are craniopharyngioma (in children) and prolactinoma (in adults).