Another Step Closer to Male Birth Control Pills

A protein might lead to an oral contraceptive for men

birth control

Scientists studying fertility in mice may have discovered a potential method for creating a birth control pill for men that involves blocking a single protein. 

These days, birth control most often falls to women, who have a variety of hormonal birth control medications available. Aside from condoms, there are few birth control options for men who don’t want a permanent vasectomy.

The most promising reversible solution for men is a product called Vasalgel—an injectable gel that plugs up the vas deferens, preventing the passage of sperm—but it has yet to be submitted for review by the Food and Drug Administration. Tests in animals suggest it is reversible and could be effective for up to 10 years with a single dose, but it does requires minor surgery, Loren Gush writes for The Verge. A male oral contraceptive would prevent unwanted pregnancies without forcing men to go under the knife. 

"Existing male contraceptives don't come close to filling the need," Aaron Hamlin, executive director of the Male Contraception Initiative, tells Amy Norton for HealthDay.

A new study published this week in Science shows that in a reversible process, blocking a single protein involved in sperm production renders male mice infertile.

Several drugs currently on the market manipulate versions of this protein to relieve symptoms of rheumatoid arthritis and to suppress immune system reactions for organ transplants. But recently, a group of scientists in Japan led by Masahito Ikawa identified an iteration of the protein only found in sperm cells, Karen Kaplan writes for the L.A. Times. Blocking the protein prevents sperm from swimming fast enough to penetrate an egg. 

Ikawa and colleagues genetically altered male mice so that they couldn't produce calcineurin. They discovered that these mice were unable to impregnate females, but were otherwise healthy. The team also dosed non-genetically altered males with a drug that blocks calcineurin. After about five days, the male mice were infertile. But when the mice went off the drug, they could once again sire offspring within four or five days, Gush writes.

While this is a promising development, male birth control pills won't show up at the pharmacy anytime soon. There is still question of its effectives and safety for human use. Even so, the presence of drugs that act on similar proteins already on the market could mean faster production of the contraceptive. 

"It is important that we find an effective and reversible contraceptive option to allow men more control over their own reproductive futures," Ikawa tells Norton. "The findings of this study may be a key step to giving men that control."

Editor's note (October 9, 2015): This story has been updated to clarify that vasalgel is still in early stages of testing and is not currently under review by the Food and Drug Administration.

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