Men willing to play a more active role in birth control can look forward to contraceptive choices other than condoms that range from vasectomy to hormones to sitting on hot rocks.
What males need, says Elaine A. Lissner, director of the Male Contraception Information Project, is a "contraceptive supermarket" similar to what is available for women.
"When we think about contraceptive availability this way and what contraceptive supermarket is available to men," she says, "the answer is only three purely male methods exist – withdrawal, the condom and vasectomy. This contrasts with the list for women – the diaphragm, the sponge, IUDS, the pill, cervical caps, 'morning after' pills, Norplant, Depo Provera, natural methods, ovulation detectors, the female condom, foams, jellies, suppositories, sterilization and more".
What's being looked at in male contraception?
Sitting on sun-baked rocks is an ancient folk-medicine contraceptive that has proven effective for up to six months. The deleterious effect of heat on male fertility has been known since the time of Hippocrates and heat methods are now being "re-discovered" as the newest method of male contraception. Heat applied to the testicles derives its effectiveness from the simple fact that the testes must be several degrees cooler than normal body temperature in order to maintain proper spermatogenisis. The heat treatment most popular today consists of sitting in water deep enough to only cover the testicles that is heated to 116 degrees Fahrenheit for 45 minutes a day for three weeks. Hot packs or heating pads may be substituted for wet heat. (And, yes, sun-baked rocks can be used in areas where fuel and water are scarce.)
Asian scientists have found that refined plant extracts used in Chinese medicine produce antifertility effects in male mice and human males without significant toxicity or side effects. One extract, highly purified triptolide from Trypterygium wilfordii, may prove suitable as a male contraceptive if adequate safety and efficacy can be established.
In the West, researchers are focusing their attention on nonhormonal and hormonal alternatives for males who want to share the responsibility of birth control. Nonhormonal methods fall into primary categories: orally active agents and immunocontraceptive approaches. Product testing of these approaches is lagging behind the testing of hormonal approaches, and research has produced few promising leads despite numerous animal studies the past few years. Recent research focusing on identifying analogs of lonidamine – an anticancer drug – that will be effective but not toxic, has produced two orally active derivatives that appear promising. In a small animal model, these compounds promoted the release of immature sperm lacking fertilizing capacity.
Hormonal contraceptive research is currently pinpointing the effectiveness of hypothalamic peptide, gonadotropin-releasing hormone (GnRH), pituitary peptides follicle-stimulating hormone (FSH) and luteinizing hormone (LH). In general, formulation of progestin and an androgen have induced azoospermia, which is an absence of living spermatoza (sperm) in semen, and significant oligospermia, which is a subnormal concentration of spermatoza in semen, more quickly than androgens alone. This combination effectively suppresses release of FSH and LH, suppressing testosterone and sperm production. The addition of a progestin to these formulations also permits the use of less testosterone – resulting in fewer side effects such as acne, weight gain or adverse reductions in serum lipids, especially HDL-cholesterol. The goal of several ongoing clinical trials involving androgen/progestin combinations is to determine optimal dose combinations that induce high rates of azoospermia and severe oligospermia while maintaining normal serum lipid levels.
Vasectomy is still the surgical contraceptive of choice for men. Vasectomy-based methods rely on cutting, blocking or otherwise limiting fertility in the vas deferens, the passage through which sperm travel to reach the penis.
Although various methods of male contraceptive appear promising, none can help control the spread of disease. The condom still rates number one in that category.