Approximately 15% of couples are unable to conceive after one year of unprotected intercourse.
A male factor is solely responsible in about 20% of infertile couples and contributory in another
30-40%.1 Azoospermia, defined as complete absence of sperm from the ejaculate, is present in
about 1% of all men2 and in approximately 15% of infertile men3. Azoospermia is different from
aspermia, in that aspermia is the complete absence of seminal fluid emission upon ejaculation.
Differentiation of azoospermia from severe oligospermia is accomplished by examination of the
pellet of a centrifuged semen sample on at least two occasions. This review offers
recommendations for diagnosing and defining the etiology of azoospermia. Patients with severe
oligospermia may be evaluated in a similar manner.