Perspectives and Editorials

Male contraception has been limited to use of the condom and vasectomy. The challenge of developing a new male contraceptive has loomed as a goal in the field of andrology for many years. In 1990, the World Health Organization released the results of the first multicenter clinical trials of a hormonal contraceptive regimen—weekly intramuscular injections of 200 mg testosterone enanthate—that caused azoospermia in 60% of the men tested after 120 days. At the time, it was a much debated topic whether complete azospermia, zero sperm in the ejaculate, was a necessary standard for effective fertility regulation, given that suppression of conceptive efficiency exceeds 95% when sperm concentrations in the ejaculate fall below 3 million sperm/mL. The World Health Organization disbanded its Task Force on Male Contraception in 1990, leaving the research community without a central forum to analyze and discuss results and consider new contraceptive development. Beginning in 1997, a group of clinical and basic researchers began holding an annual summit meeting to explore options to accelerate the pace of drug discovery and testing in this area. Today, hormonal contraception is the only new male method close to the market place, although much work remains to improve the formulations and delivery of the steroids that are its active agents. In 2006, at the most recent 10th Summit Meeting on Hormonal Male Contraception in New York, a set of guidelines was drafted and released to provide benchmarks for future development and testing of hormonal methods. In this issue, we are reprinting the Guidelines. We note that suppression to less than 1 million sperm/mL, not azospermia, was set as the recommended standard. The debate over this issue has been addressed, and the field of male contraceptive development has progressed.