Male fertility regulation: recent advances.

Acceptable antifertility drugs for men are proving difficult to produce. Such drugs must aim to achieve complete azoospermia over a long period. This requirement may be relaxed only if it can be shown that the residual sperm produced by men whose spermatogenesis has been suppressed by antifertility drugs to oligospermia are incapable of fertilizing ova. Hormonal methods involving suppression of the secretion of gonadotrophin hormones by the pituitary gland invariably require androgen supplementation, and the use of steroids either alone or in combination requires careful monitoring for their side-effects. A chemical (non-hormonal) approach involving the incapacitation of sperm in the epididymis has been shown to be feasible in animal studies using alpha-chlorohydrin and 6-chloro-6-deoxy sugars, although such compounds cannot be developed for human use because of their toxicity. Immunological approaches have the inherent problem of delivery of the antibody to the target. While the search for new and safer chemical and hormonal approaches goes on, the recent evidence that vasectomy offers a safe surgical option leaves responsible men with some choice to add to the condom.