New Male Birth-Control Options May Be on the Way
WebMD News Archive
One approach that has been tested uses the hormone testosterone by itself,
injected once a week or once a month. This suppresses sperm counts, but the
effect varies, so a small percentage of men remain fertile. For unexplained
reasons, testosterone alone appears to be more effective in Asian men than in
men studied in the U.S., Europe, and Australia.
"The Chinese are interested in this approach and likely to be the first
to introduce it on a non-experimental basis, using longer-acting testosterone
that can be injected once a month," Amory says.
The most promising hormonal approaches for non-Asian men combine
testosterone with another substance to enhance its effect. One possibility is
combining testosterone with a chemical called gonadotropin-releasing hormone
antagonists, which block another type of hormone involved in sperm production.
But these chemicals are expensive and must be injected under the skin.
Another possibility is combining testosterone and progestin hormones. Many
researchers believe this combination is the most likely to work in non-Asian
populations, the study's authors write.
In the latest tests of male hormonal contraceptives, men have remained on
the methods for up to a year. "In all of them, once they stopped taking it,
their sperm count come up to normal within six months of stopping, and several
have had children," Baird says. "However, if you ask me, 'What will
happen if I take it for 30 years?,' we can't know that until enough men have
taken it for 30 years."
How soon could male hormonal contraceptives reach drugstore shelves?
"Twenty years ago, people were saying 'in five years' and they turned out
to be wrong, so I'm hesitant to make predictions," Amory says. "There
are technical hurdles that need to be overcome. Conservatively, let's estimate
10 to 15 years. Or if there were a major breakthrough, it could be five
- Researchers are continuing work on developing more birth-control options
- Early studies have been conducted with injections of testosterone, alone or
in combination with other substances.
- The hope is to find male birth control that has positive side effects, such
as reducing the risk of prostate and testicular cancer, acne, benign enlarged
prostate, and male pattern baldness.