Approximately a tenth of marriages in the United States are barren, and another tenth result in fewer children than desired. The husband is the cause of the infertility in about a third of these marriages.
Infertility can be due to either disorders of the hypothalamic-pituitary system, disorders of the testes, or abnormalities of the ejaculatory system. When obtaining a history, the physician should collect information about the duration of infertility, fertility in prior marriages of both the husband and wife, the presence of acquired or congenital disease that may lead to infertility, technique and frequency of intercourse, and family history of infertility. To exclude gross abnormalities of the endocrine system, the physical examination should evaluate the distribution of body hair, the presence of gynecomastia, the development of the scrotum and penis, the location of the urethral meatus, and the presence of normal vasa deferentia and epididymides. The size of each testis should be estimated. Because the seminiferous tubules account for more than 75 percent of the testicular mass, a reduction in testicular size (less than 3.5 cm in length) indicates a deficiency in the spermatogenic function of the testis. Finally, with the patient in the upright position, the Valsalva maneuver should be utilized to test for the presence of a varicocele.
The semen analysis provides a semiquantitative estimation of the severity of the dysfunction. The findings are usually considered normal if the semen coagulates and then liquefies, the volume is 2 to 5 mL, the sperm count is greater than 20 million per milliliter, more than 60 percent of the sperm are actively motile, and more than 60 percent have normal morphology. If no sperm are present, the term azoospermia is used; if sperm are present but the count is less than 20 million per milliliter, the patient is considered to have oligospermia. In the azoospermic man with normal-sized testes, the differential diagnosis includes hyalinization of the seminiferous tubules, Sertoli cell-only syndrome, gonadotropin deficiency, ductal obstruction, and maturation arrest. Plasma testosterone, LH (luteinizing hormone), and FSH (follicle-stimulating hormone) measurements are helpful in separating these conditions. With hyalinization of the seminiferous tubules LH and FSH are elevated, and plasma testosterone is low or borderline normal. Men with Sertoli cell-only syndrome usually have normal LH and testosterone, but elevated FSH levels. In gonadotropin deficiency LH, FSH, and testosterone are low, and in ductal obstruction or maturation arrest all endocrine studies are normal. To differentiate between the last two disorders, a testicular biopsy is necessary. In oligospermic patients, if the history and physical examination are normal, it is unlikely that any further laboratory investigation will be useful in defining the etiology. These patients are usually classified in the large group termed idiopathic oligospermia.