Scientists believe they may have reached a breakthrough in developing a birth control pill for men.
If the pill is eventually approved, it could help to balance the contraceptive burden that is currently placed on women and people who ovulate.
After being tested on mice, the pill was found to be 99% effective in preventing pregnancy with no side effects.
It works because a molecule called YCT529 in the pill was found to cause a significant reduction in sperm count over a four-week period. Within four to six weeks of being weaned off the pill, the mice's sperm count returned to normal.
The group of scientists working on the pill presented these findings at this week's spring meeting of the American Chemical Society.
The next step is to test the pill on humans to determine whether it works just as effectively, and again without any side effects.
"If everything goes well and the drug shows safety and efficacy in the clinical trial, it’d be safe to assume that we could see this on the market within this decade and perhaps as early as in five years."
However, al Noman also warned that this process could take longer. He pointed out that scientists have been trying "for decades" to develop an effective birth control for men, but none has ever made it to market.
This new pill is especially promising, he said, because it is non-hormonal. Many of the previous, failed male contraceptive pills worked by targeting the sex hormone testosterone, which led to unwanted side effects including raised cholesterol and depression.