A team of British scientists have made a breakthrough in the search for a male contraceptive pill.
They claim to have found a way to 'switch off' sperm's ability to swim, preventing them from being able to fertilise eggs.
"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," said lead researcher professor John Howl of Wolverhampton University.
Howl and his team joined teamed up with IVF specialists from Aveiro University in Portugal to create and test the compound, a cell-penetrating peptide that stops sperm tails from wiggling.
"Nobody else has ever done this before," Mr Howl told The Daily Mail.
The scientists hope to begin testing on animals in the next three years, thanks in part to the team being given a £175,000 grant.
It typically takes three to five years to bring a new drug to market after animal trials, so the final product, if successful, could be available as early as 2021.
With global sales of contraceptives topping £13 billion a year, the market for a reversible male contraceptive looks to be huge.