For most American couples, the responsibility of preventing unwanted pregnancy rests with the woman. That's true for a variety of reasons, but one fact is inescapable: Women have more birth-control options, including pills, diaphragms, IUDs, implants, caps, gels, foams, creams, injections and suppositories. Men have two choices: wear a condom or get a vasectomy.
Endocrinologist William J. Bremner says men might be more likely to take responsibility for birth control if they had more methods to choose from. Bremner is director of a new male contraception research center at the University of Washington in Seattle, created with $9.5 million in funding from the National Institutes of Health.
While women sometimes wonder aloud why there isn't a version of the birth-control pill for men, Bremner thinks the ultimate goal should be to create an array of new male methods to match different needs and preferences.
"Some men can't remember to take a pill, some don't like shots," says Bremner. "Some people like Chevys, some like BMWs. Seems to me you've got to have some range of product choice."
Still, much of the current research in male contraception focuses on the same goal: finding ways to alter hormone levels to stop sperm production.
Scientists know that the pituitary gland uses hormonal messengers to signal the testes to make sperm and testosterone. The pituitary gland monitors testosterone levels in the blood; when they reach an adequate level, the gland stops sending signals to the testes.
Scientists also know that it's possible to quiet the pituitary gland's signal to the testes by raising blood testosterone levels artificially with synthetic hormones.
Getting the job done, however, may require amounts large enough to cause unwanted side effects, such as aggression, impotence and cholesterol problems. So contraceptive researchers have experimented with giving men small doses of testosterone combined with progestin, a synthetic version of the female hormone progesterone, which also suppresses sperm production.
In a study published in August in the Journal of Clinical Endocrinology and Metabolism, researchers at the Harbor-UCLA Medical Center in Torrance brought sperm production to a virtual halt in a group of men who received regular testosterone injections and had tiny progestin-packed rods surgically implanted under their skin. The only significant side effect the men experienced was modest weight gain.
The study's lead, UCLA endocrinologist Christina Wang, is studying the effectiveness of an implant for men that combines testosterone and progestin. Dr. Wang predicts, however, that a combination male contraceptive using progestin and injected testosterone that's being developed in Europe will be the first hormonal birth-control method for men to reach the U.S. market, possibly within a few years.
For now, injecting testosterone is the most reliable way to deliver the hormone; testosterone pills aren't absorbed well and can damage the liver. Some medical experts, however, doubt that men will be enthusiastic about taking a shot, perhaps as often as once a month, to prevent pregnancies. "That's not going to fly," says Dr. David F. Archer, a contraceptive researcher at Eastern Virginia Medical School, in Norfolk, Va. For needle-shy men, however, Archer and others say it's possible that a safe and effective pill will be developed.
Bremner disputes the common notion that men aren't willing to take responsibility for birth control, citing National Academy of Science statistics showing that U.S. couples rely on male condoms and vasectomy in nearly one-third of cases.
But we can't help but wonder: Will women trust men who say they're on the pill? We asked Nicole Beland, who writes the "Girl Next Door" advice column in Men's Health magazine. She said it depends on the circumstances. A guy you just met in a bar? "Absolutely not," Beland says. But for couples in committed relationships, she says the male pill just might work. "If we trust men to be faithful," she says, "then I think we can also trust them to take the pill."
Other women, however, might need more convincing about their partners' sense of responsibility.
"I can't even trust my husband to remember to pick up my dry-cleaning," says my friend Ellen. "Why would I trust him with contraception?"
Massachusetts freelance writer Timothy Gower can be reached by e-mail at firstname.lastname@example.org. The Healthy Man runs the second Monday of the month.