FIVE THINGS ABOUT A BIRTH CONTROL PILL FOR MEN

1 IT STOPS SPERM FROM SWIMMING

A breakthrough scientific discovery that could be key to developing a male contraceptive pill changes the way human cells work, switching off the ability of sperm to swim, rendering men temporarily infertile.

2 IT USES PEPTIDES

Peptides are short chains of amino acids. They occur naturally but can be created synthetically. The breakthrough came after scientists at England’s Wolverhampton University found some peptides could penetrate sperm cells. Then fertility experts at the University of Aveiro in Portugal, who identified the protein that drives sperm to swim, created a compound that turns the protein off.

3 IT WORKS FAST

Lead researcher professor John Howl of Wolverhampton University said the new compound, made in the lab, showed immediate results. “The results are startling — and almost instant. When you take healthy sperm and add our compound, within a few minutes the sperm basically cannot move,” he said.

4 IT’S ONLY TEMPORARY

The discovery raises the prospect of a fastacting pill or a nasal spray that a man could take hours or even minutes before sex. But researchers believe the effects of would wear off in a matter of days.

5 IT COULD CHANGE FAMILY PLANNING

Women are typically advised to stop taking birth-control pills weeks or even months before trying to conceive. Family planning experts said a reversible male contraceptive could also benefit couples where the woman does not want to take birth-control pills. The compound has been tested in the lab on bovine and human sperm, with live animal tests to start within three years.