In the wild, most species are seasonal breeders and only have sex for procreation. The bear, for example, mates in the fall so it can have its offspring in the spring when resources are at their greatest to ensure survival. The bear’s sperm production is then turned off.

Alas, we are not bears.

That’s why researchers all over the globe are currently working to develop a safe and effective contraception for males to temporarily turn off sperm production. This testosterone-based “male pill” would provide men with more birth control options—and possibly increase reproductive responsibility—while potentially limiting the unwanted side effects of the male hormore testosterone.

Researchers at the University of Washington are working on a method of birth control using testosterone to reduce sperm production. The injectable testosterone undecanoate, which is chemically synthesized from a precursor in Mexican yams, works as a contraceptive by suppressing the two hormones that travel from the brain to the testes to make sperm and testosterone. This halts sperm production, and the external testosterone replaces the natural form.

High levels of testosterone are often associated with increased sexual drive and aggressive behavior. “If you take testosterone, it’s basically like taking steroids,” says Kamal Harb, health educator at SF State. However, since information is limited during such early stages of research, he insists it’s uncertain whether the extra doses of the male hormone will cause any behavioral changes.

Dr. John Amory, associate professor at the Center for Research and Reproduction and Contraception at the University of Washington, claims males are left with a healthy level of testosterone and sexual function, and the quality of life is preserved.

Although this up-and-coming contraceptive has been dubbed the “male pill,” there currently isn’t a pill form in development. In clinical trials, all testosterone is administered by injection, patch or gel.
Like the female contraceptive that uses estrogen and progesterone to shut off the release of eggs, male contraceptives use testosterone and progesterone to stop the production of sperm. Although it can take about two months of t-injections to reduce the sperm count to zero, normal sperm production can return within two to four months upon ending the injections.

In clinical trials, t-injections have resulted in a sperm count of zero in 70 percent to 90 percent of men. While suppressing a male’s sperm count to 3 to 5 million per milliliter of ejaculate is enough to reduce the chance of pregnancy, getting it to less than one million would make it 99 percent effective, the same as female birth control, according to Amory.

Right when progress is looking up, however, researchers are hitting a snag: the male contraceptive mysteriously doesn’t work for all men, and it appears that ethnic differences are connected with the inconsistencies. World Health Organization studies indicate that complete sperm suppression with t-injections occurred in 90 percent to 100 percent of Asian males, while only 60 percent of Caucasian males suppressed to zero with the same treatment.

Possible side effects of a male contraceptive could include weight gain, an increase of the oiliness of the skin and acne—side effects similar to those of the female pill. Amory also notes that they have seen about a 10 percent reduction of the good form of cholesterol, called HDL cholesterol, during clinical trials. “We don’t know what that means, but we’re not crazy about it,” he says. “But just like the pill for females, it has its pros and cons.” Another common concern is the possible connection between testosterone and prostate cancer, but Amory insists it’s not clear whether it’s going to be a beneficial or harmful factor.

Just as the female pill might reduce painful periods, clear up acne and reduce the risk of ovarian cancer, a male pill may also offer non-contraceptive benefits. Researchers welcome the possibility that it could also reduce the risk of testicular and prostate cancer, clear up acne and maybe even reduce the risk of male pattern baldness.

Since the development of the female oral contraceptive pill in the 1960s, women have enjoyed a wide variety of safe and effective birth control options. Men, however, besides abstinence and the ineffective withdrawal method, have only had two options for the last century: condoms and sterilization. Family Planning studies show that men account for about one-third of all current contraception, of that 20 percent being condoms and about 15 percent vasectomies. “What comes as a big surprise to people is that men are actually big contraceptors,” Amory says.

So, why has a male pill taken so long? “When it comes down to it, men and women are simply different,” Amory says. “Women make one egg a month; men make a thousand sperm a second. It’s a different biological challenge.”

“The challenge to develop reversible methods of contraception for men is a complicated one,” according to Planned Parenthood. “Healthy men are always producing sperm. The continuous fertility of men does not offer the opportunities for reversible intervention that are offered by women’s cycles of fertility.”

Another question is whether or not men would be willing to endure monthly t-injections or take a daily pill, when available. “I think as gender roles have changed, there’s more and more equality in relationships,” says Gilbert Herdt, professor and director of human sexuality studies at SF State. “Men have more of a sense of sharing, and the message that they need to be more responsible is getting out.” But Harb believes men won’t be interested. “Guys don’t like going to the doctor,” he says. “Will they really go for a monthly shot?”

Amory estimates a male contraceptive will be available in the United States in five years, which could cost anywhere from $30 to $60 per month. He predicts China and Europe, who are more advanced in male contraceptive studies, could possibly produce a male pill much sooner. “We’re making progress,” he says. “Hopefully within a few years we’ll have something on the market for men to use.”