We are one step closer to bringing gender balance to the contraceptive burden, thanks to a breakthrough male birth control pill. 

A new non-hormonal contraceptive pill for men has been found to be 99 per cent effective in preventing pregnancy in mice with no observed side effects. The scientists working on the medication presented the findings yesterday (March 23) at the spring meeting of the American Chemical Society. 

The team gave male mice a daily dose of a molecule called YCT529 over four weeks and found that their sperm count plummeted, with no other reported side effects. “When we went to even 100 times higher dose than the effective dose, the compound didn’t show any toxicity,” Md Abdullah al Noman told NewScientist. By six weeks after the mice stopped receiving the pill, they could reproduce normally again.

The team will now move on to human trials, which they are aiming to begin in the US later this year. If successful, the pill could be on the market within five years. However, success is not guaranteed as it can be difficult to predict if a compound that looks good in animal studies will also pan out in human trials. 

Norman, however, remains optimistic. “We are very excited and hopeful about this drug,” he told i. “If approved, this could be the next breakthrough in birth control pills since the first female birth control pill in 1960.” 

Over the years there have been many attempts to develop a male contraceptive pill, and there are several compounds currently undergoing clinical trials. Thus far, no treatment has passed human clinical trials. Many of these previous drugs, however, suppressed the male sex hormone testosterone, which can cause weight gain, depression and blood clots alongside other side effects. While side effects such as these are commonly experienced by women on birth control, it seems when it comes to men there is a much lower tolerance for them.