Male contraceptive pills are effectively preventing pregnancy - Study

The idea is that men can take the pill an hour before intercourse and focus on timing as it wears off.

For years, females have been using hormonal contraceptive drugs while men their only contraception is condoms.

The female contraceptive pill does not involve any hormones and scientists say that is one of the advantages they are investigating a method that will not remove testosterone and cause any side effects of male hormones.

Instead, the "swimming sperm" switch targeting is a cell-signaling protein called soluble adenyl cyclase or SAC. Male test pills block the SAC.

In an earlier study in mice, funded by the US National Institutes of Health, a single dose of the drug called TDI-11861, blocked sperm before, during and after intercourse. The effect lasted for about three hours and by 24 hours, it seemed completely exhausted.

One of those scientists, Dr Melanie Balbach from Weill Cornell Medicine in New York, said it was proved to be an easy-to-use contraceptive.

If it eventually works in humans, men can swallow only when necessary. They can make daily decisions about their parenting.

Scientists say the pill can help in parenting but it does not protect against sexually transmitted diseases, a condom would be needed for that.

Prof Allan Pacey,  Professor of Andrology at the University of Sheffield, said: "There is a huge need for an effective, viable oral contraceptive for men and although many different methods have been tried over the years, none have arrived in the market.

It is intended that more tests will be done, first on rabbits and then on humans.

"The method described here, to knock out a key enzyme in sperm that is important, is a completely new idea. The fact that it can act, and be reversed, so quickly is very exciting."