Live sperm samples displayed on a monitor. Sumit Dayal Bloomberg | Getty Images

Sujoy Guha, biomedical engineer and inventor of the reversible inhibition of sperm under guidance (RISUG) male contraceptive treatment Sumit Dayal Bloomberg | Getty Images

Another compound, called gendarussa, which is derived from an Indonesian shrub, interrupts the way sperm enter an egg to fertilize it. Clinical trials in Indonesia have found that the compound is highly effective, with few side effects, though larger studies would be needed before the drug could be submitted for approval by the FDA.

Decades of development

Where's Big Pharma?

Despite decades of development, few techniques have moved past initial phases of testing. Pharmaceutical companies have not been interested in developing a male contraceptive beyond what is already on the market. Efforts in the early 2000s from small pharmaceutical companies, such as Organon and Schering, have stalled. A spokesperson from Merck, which acquired Organon's parent company in 2009, says this is not an active area of research or interest. Bayer, which acquired Schering in 2007, reached a similar conclusion: "Ultimately, the decision was made to halt male contraceptive research, and we currently do not have plans to pursue in the future," a spokesperson said via email. Experts have some ideas as to why big pharmaceutical companies might not be interested. According to Kenneth Kaitin, professor and director of the Tufts Center for the Study of Drug Development, marketing a male contraceptive might be harder than some might think — it would only appeal to men in long-term heterosexual relationships with partners of reproductive age. And since the drug wouldn't be combating a rare, life-threatening illness but would rather serve patients who are already well, pharmaceutical companies would have to make it affordable to the average consumer. All in all, Kaitin says, they probably don't think they would make much money off this kind of drug. "Getting women to stop taking her drug for a man to start taking his drug, that would take a lot of selling," Kaitin says.

Getting women to stop taking her drug for a man to start taking his drug, that would take a lot of selling. Kenneth Kaitin professor and director of the Tufts Center for the Study of Drug Development

"Ultimately, it comes down to capitalism," says Allan Pacey, a fertility expert at the University of Sheffield. And so far that has meant that male contraceptives don't make financial sense. It's also risky. A male contraceptive would serve a population that's already healthy with the goal of preventing pregnancy, for which men don't carry the physical risk. That would mean that regulators would have a very low bar for side effects. And for the intervention to work, it couldn't let even one viable sperm through—it just takes one to get a woman pregnant. But the argument that there's no market for male birth control is deeply flawed. Research has discovered that men, in fact, want more contraceptive options. "A key aspect is that it gives men the opportunity to be involved in family planning. At the moment, they are excluded from being able to shoulder the burden," says Richard Anderson, a professor of clinical reproductive science at the University of Edinburgh. That especially makes sense for heterosexual couples in which the woman can't take birth control for medical reasons, such as a high risk of blood clots.

Market demand