There are various causes of hypogonadism, including:
Klinefelter's syndrome. This syndrome involves the presence of abnormal sex chromosomes. A male normally has one X chromosome and one Y chromosome. The Y chromosome contains the genetic material with the codes that determine the male gender, and related masculine characteristics and development. Males with Klinefelter's syndrome have an extra X chromosome, which causes abnormal development of the testicles.
Undescended testicles. (see above)
Hemochromatosis. This condition is marked by too much iron in the blood, and can cause the testicles or the pituitary gland to malfunction.
Testicular trauma. Damage to the testicles can affect the production of testosterone.
Cancer treatment. Chemotherapy or radiation therapy, common treatments for cancer, can interfere with testosterone and sperm production by the testicles.
Normal aging. Older men generally have lower levels of testosterone, although the decline of the hormone varies greatly among men.
Pituitary disorders. Problems affecting the pituitary gland, (a small organ in the middle of the brain) including a head injury or tumor, can interfere with the gland's ability to send hormonal signals to the testicles to produce testosterone.
Medications. Certain drugs can affect testosterone production. These include some commonly used psychiatric drugs.
How Is Hypogonadism Treated?
Treatment for hypogonadism depends on the cause. Male hormone replacement (testosterone replacement therapy or TRT) often is used to treat disorders of the testicles. If the problem is related to the pituitary gland, pituitary hormones may help increase testosterone levels and sperm production.