It has been 51 years since the first birth-control pill became available in the U.S., bringing dozens of contraceptive options for women in its wake. There are currently two options on the market for men—vasectomy or a condom.

The research pipeline is full of possibilities, though. Scientists at Columbia University Medical Center have halted sperm production and started it again in mice with no apparent side effects, using a drug that blocks receptors for vitamin A. An injectable synthetic substance, in Phase 3 clinical trials in India, sabotages sperm as they leave the testes and lasts for years.

Hormone gels and implants that can make men temporarily infertile are already on the market in the U.S. for other purposes. Nonhormonal methods—removing vital proteins from sperm, thwarting their ability to penetrate eggs or zapping them with ultrasound waves—are being investigated, as well.

"This is the male method moment," says Elaine Lissner, director of the nonprofit Male Contraception Information Project, a San Francisco advocacy group. "The future looks different from the past."

Finding a safe and effective contraceptive for men has been difficult in part for biological reasons.

It would have to be strong enough to halt production of tens of millions of sperm a day, yet not harm libido or sexual function. To improve on vasectomy, it would need to be reversible and have minimal side effects, since men themselves don't face the possibility of pregnancy. For example, some female birth-control pills raise the risk of blood clots, but pregnancy carries 10 times that risk, says John Amory, a professor of medicine and specialist in male reproduction at the University of Washington. For a male method, he says, "the bar is very, very high."

Funding is an obstacle too. Several drug companies, after initial interest, have pulled back from the area amid concerns about safety and marketability. The National Institute of Child Health and Human Development (NICHD) and the World Health Organization fund much basic research.

Yet in surveys, more than 50 percent of men say they would be willing to use a hormonal contraceptive to relieve female partners of the burden and to exert more control.

"It's scary to get that phone call. Or that text message. The one every guy on earth fears," says Ezekiel Setne, 20, a University of Southern Indiana premed student who says he's had close calls with condoms. "I would love any effective male birth-control method."

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