Management of male infertility.

The causes of infertility are known in a small proportion of patients, and only a few are treatable: gonadotrophin deficiency, genital tract obstruction, sperm autoimmunity, coital dysfunction and reversible effects of toxins, drugs or intercurrent illnesses. Other patients have reduced sperm quality or function that may be associated with previous testicular damage, varicocele or non-specific genital tract inflammation. No treatments have been proved to increase semen quality and fertility in this group; intracytoplasmic sperm injection is the most appropriate management if a natural pregnancy is unlikely to occur. Apart from the transmission of genetic and chromosomal disorders and a small increase in the number of sex chromosomal aneuploidies associated with severe spermatogenic defects, the risk of serious adverse effects in intracytoplasmic sperm injection offspring is low. The pathogenetic mechanisms of the most common forms of defective sperm production are unknown, which prevents the logical development of effective treatment.