One couple in 10 seeks medical help because of infertility. A 1982–85 multicentre study by the World Health Organization found that in 20% of cases the problem was predominantly male, in 38% the problem was predominantly female, in 27% abnormalities were found in both partners, and in the remaining 15% no clear-cut cause of infertility was identified. 1 Diagnostic advances are progressively decreasing the proportion of couples classified as having idiopathic infertility. It is also now recognised that no simple tests can indicate the likelihood of pregnancy in a union in which the man is an infertile partner. The duration of infertility provides one of the most significant prognostic indicators; couples with a history of primary infertility longer than 3 years are very unlikely to achieve an unassisted pregnancy. 2 In this review of male infertility I will concentrate on recent major developments in diagnosis and management.

Major causes of male infertility To achieve fertility a man requires normal spermatogenesis, successful epididymal maturation and storage of sperm, and normal sperm transport and accessory gland function, together with appropriately timed intercourse. Male infertility can be categorised as due to pretesticular, testicular and post-testicular factors (panel 1), and for detailed consideration of these factors the reader is referred elsewhere. 3 Until recently, in up to 40% of men with abnormalities of sperm production, no specific aetiological factor could be found, but several advances, and two in particular, have resulted in a better understanding of the potential causes.