Looking for the "male pill".

Researchers are pursuing 2 approaches to developing a male contraceptive drug. 1 approach centers around suppression of sperm production the other around blocking conception. Researchers are looking at introducing hormonal contraceptives into men's bodies via injections or implants to stop sperm production. Both forms of these possible male contraceptives will not be available for many years, however. A WHO study on testosterone enanthate of men in 7 countries reveals total suppression of sperm production occurred in almost all the Asian men, but only about 60% suppression occurred in other ethnic groups. A current WHO study is examining whether a hormonal contraceptive which is not 100% effective can be useful if it would be more effective than barrier methods. The Population Council is conducting research on 2 capsule implants with 1 capsule releasing luteinizing hormone releasing hormone 13 to halt sperm production while the other releases an androgen to maintain sex drive. Animal tests indicate complete contraception with no side effects. The other possible means of suppressing sperm production is administration of a cottonseed oil extract called gossypol which appears to stop sperm production thereby eliminating the need for concurrent androgen administration. Yet it does cause potassium depletion in some men which can result in arrhythmias. An antifertility vaccine comprises the 2nd approach. Several US researchers are exploring an antifertility vaccine to produce antibodies only to the specialized sperm surface needed to attach to the egg. The 1st antifertility vaccine would probably be in pill form and a woman's contraceptive since it is earlier to target the smaller number of sperm in the oviduct than in the testes.