An evaluation of the reproductive endocrine status is an essential component in the investigation of all male partners with either an abnormal physical examination suggestive of a disorder in testosterone production and action, an abnormal semen examination, or evidence of impaired sexual function. Initial laboratory assessment of the hypothalamic- pituitary-testicular axis includes the measurement of circulating levels of LH, FSH, and testosterone. The differential diagnosis and treatment of endocrine- dependent male-factor infertility is based on the history, physical examination, and reproductive hormone levels. Hypogonadotropic hypogonadism, also referred to as secondary hypogonadism, can occur as the congenital condition idiopathic hypogonadotropic hypogonadism (IHH). Androgen receptor abnormalities are rarely amenable to hormone therapy. Testosterone replacement therapy available in the United States includes oral, intramuscular, transdermal, and buccal preparations. A number of non-FDA-approved drugs and supplements are marketed as alternative therapies for declining androgens and decreasing libido and potency in older men.

Infertility is due to a significant male factor alone, whereas combined male and female factors are present in an additional 20%. Thus, a male factor is involved in approximately 50% of infertile relationships. The primary goals of the evaluation of the male presenting with infertility are to identify: etiologic conditions, irreversible conditions, irreversible conditions not amenable to assisted reproductive techniques, medically significant pathologies, and genetic etiologies. Bilateral cryptorchidism results in a significant decrease in spermatogenesis, while the effect of unilateral cryptorchidism appears to be much milder. Approximately 50% of testicular cancer patients have subnormal sperm densities prior to chemotherapy. Of note, of those with oligo- or azoospermia, 75% normalized during surveillance. Diethylstilbestrol (DES) was given to pregnant women in the 1950s, and reports of epididymal cysts and cryptorchidism in males with prenatal DES exposure have raised concerns about effects on fertility. Exogenous androgens are well known to induce hypogonadotropic hypogonadism.