PIP: 80% of the world's contraceptive users are women. This gender-based usage has occurred due to the emphasis of family planning programs and contraception research on female methods. Even if men desired to take responsibility for contraception, only the condom and vasectomy are available and have a reasonable assurance of protection. The Population Council has been researching male contraception through its Center for Biomedical Research. An oral contraceptive derived from gossypol, a cottonseed plant pigment, is being tested after successful clinical trials were performed in China during the 1970s. Also being investigated are male hormonal methods that regulate sperm production while protecting against loss of potency, loss of libido, and changes in secondary sex characteristics. A hormonal implant, effective for one year, has been in Phase I clinical trials since 1993. A small Phase I clinical trial is in process for a vaccine/implant for men that is effective for one year. Testing with injectables for men has suggested that different hormonal mixes could increase cardiovascular risk for men and exacerbate prostate cancer. Research has focused on new materials for condoms. Kraton-type materials are made from block copolymers and polyurethanes, and these condoms have shown some promise. The advantages of these products are that they are allergen-free, less susceptible to oxidation, and can be of thinner construction, which would increase sensitivity and acceptability. The percutaneous chemical method of no-scalpel vasectomy has been studied as a means of blocking passage of sperm in the vas deferens. In China and India, injections with liquid silicone, polyurethane, neem-oil, and n-butyl-cyanoacrylate mixed with phenol are being studied. Zinc injections that cause the epididymis to atrophy are being tested on animals in the US. Lasers and fiber cautery are other methods under investigation. Increased funding is essential for these and other research efforts.