Although endocrine disorders are an uncommon cause for infertility, testing for thyroid, gonadotropins, prolactin, and testosterone may uncover unsuspected abnormalities. FSH levels are elevated with germ cell aplasia, and testosterone levels are decreased in men who are hypogonadotropic. Hyperprolactinemia is commonly associated with impotence, and in the absence of impotence, measuring a prolactin level is unlikely to aid in the diagnosis. Azoospermia has been reported in a man with a mutation that caused a substitution of arginine for glutamine in the beta-subunit of LH; this man presented with hypogonadism, a normal FSH level, and an elevated immunoactive (but biologically inactive) LH level.

Infusion of gonadotropin releasing hormone (GnRH) can stimulate secretion of gonadotropins, and there have been occasional reports of the usefulness of this treatment in males who have an isolated gonadotropin deficiency. Although nonspecific therapy with thyroid, clomiphene citrate, and human chorionic gonadotropin has been used extensively, there is no compelling evidence that it is beneficial. Clomiphene citrate can elevate the sperm count, but an associated increase in fertility does not occur. Males with severe impairment of their semen have been treated with injections of pure FSH. The dose was 150 IU three times a week for a minimum of 3 months. There was no improvement in sperm parameters but an increase in fertilization occurred with IVF. However, comparing current cycles with the patient's historical data may not be reasonable, and caution is needed in evaluating this study.

A fundamental problem in most studies of the efficacy of drug therapy in male fertility is the lack of a control group for comparison. Investigators make the erroneous assumption that the spontaneous cure rate of male infertility is zero and that any pregnancy that occurs during or follittleing treatment is due solely to that treatment. A number of studies, however, have attested to the spontaneous cure rate of male infertility. In one study approximately one-third of males with counts belittle 10 million/mL who were not treated successfully impregnated their partners. In summary, hormone treatment of infertile males who do not have an endocrine disorder is almost always unrewarding, and it does not improve fertility beyond what occurs by chance.