the latest development in the search for a male birth control pill isn't a pill at all-it's an injection.
a may study in the journal of clinical endocrinology and metabolism revealed that beijing researchers have successfully tested a testosterone-based injection, intended to be used monthly by men to induce temporary sterility. it proved to be 95 percent effective, almost equivalent to the female birth control pill, but some doctors-and potential patients-are skeptical.
elaine lissner, director of the male contraception information project, identified a need for a male hormonal contraceptive.
"vasectomy is permanent, and condoms are not foolproof," she said in a press release. "a reversible, reliable long-term method would meet a big need."
indeed, researchers have been struggling to develop a male equivalent to the female birth control pill since the 1960s, when the female pill was introduced. headlines such as "male birth control pill soon available" appear regularly, without the hoped-for results.
"they've been saying it's going to be available in five to seven years for the last 40 years," brian alexander, a sex columnist for msnbc, told npr.
but scientists from the national research institute for family planning in beijing, led by dr. yi-qun gu, believe that they may have finally found a safe, reliable hormonal contraceptive for men. according to abc news and the independent, the 1,000 male participants who took part in the two-year study were all aged 20 to 45 and had each fathered at least one child. they were each given monthly injections of testosterone undecanoate (tu) in tea seed oil, as they continued sexual relations with partners aged 18 to 38 who had no known reproductive problems. among the men whose sperm count decreased as expected within the first few months, the hormone was 98 percent effective. it was 95 percent effective overall.
these results aren't perfect, and the drug isn't nearly as reliable as the female birth control pill, but according to dr. john k. amory of the university of washington in seattle, it's not bad either.
"they went down to 1 million sperm in a milliliter of semen from the normal 20 to 200 million sperm per milliliter," he told abc news.
an immediate problem, though, is lag time. since the drug takes about a month to lower sperm count, it would be most useful in committed relationships, rather than casual encounters.
"it's certainly not a morning-after pill," said dr. ronald swerdloff, a researcher at the university of california los angeles. "it's really designed for longer term planning."
and scientists are quick to acknowledge the unintended and often dangerous side effects of taking testosterone. in some cases, it can cause permanent damage.
"in men who have not tested their fertility and may already have impaired fertility, giving testosterone to lower sperm count can make them permanently sterile after the testosterone has stopped," said dr. lawrence ross, former president of the american urological association. "over time it can cause the testes actually to involute and shrink. we've seen this in athletes. they become permanently scarred and don't recover."
according to alexander, a testosterone injection can also cause hair loss and weight gain. but not all scientists agree that these side effects are applicable to tu. amory, for instance, distinguished tu from other testosterone-based hormones such as steroids, which, once the human body converts the excess hormone into estrogen, can cause the development of breast tissue and other female attributes. swerdloff concurred, expressing confidence that the tu treatment would be safe.
"it's quite clear from all the data that we collect that this is a reversible process," he said. "the permanent sterility in steroid abusers is a complicated area because almost none of the data are what you would call scientifically based. the data are anecdotal experiences, in individuals who are abusing drugs."
but there are financial and political realities preventing the release of a hormonal contraceptive for men. because reliable contraceptive methods are already available, pharmaceutical companies tend not to be interested in funding new research-for both male and female contraceptive hormones. according to swerdloff, these companies believe that a male contraceptive drug would not be profitable, and more important, that its potential benefits would not offset the risk.
"these [patients] are not people who have cancer or a serious disease. they're normal people," he said. "when the only benefit is protecting against pregnancy-well, that's not curing cancer. the biggest limitation is finding a company, or the public sector, that is willing to underwrite the cost of providing family planning in a male-directed fashion to very large numbers of people, and would somehow obviate the liability."
and even if such a drug becomes available, some experts doubt that men will be vigilant enough to take it regularly. if a woman has intercourse with a new partner, she has no way of knowing if her man is telling the truth about taking the hormonal contraceptive.
"ultimately i think it's always going to come back to women. they're the ones that get pregnant," kay hymowitz, senior fellow at manhattan institute, told npr. "in relationships that are less long-term and less committed and less well defined, i think a woman would be very, very foolish not to see herself as in charge of these things."