A contraceptive pill for men could be a step closer, according to a report.
Academics at Minnesota University announced at the American Chemical Society’s yearly meeting that significant progress had been made, as they look for a product that has no side effects.
Since the female pill was made available 50 years ago, scientists have yet to pause fertility for men without huge risks.
Gunda Gerog, who leads the research team, said: ‘It would have to be soluble so it could be taken by mouth. It would start working fairly quickly and it wouldn’t diminish libido. It would be safe even if taken for decades.
‘And because some users would eventually want to have children, its impact on fertility would be reversible, with no lingering ill effects on sperm or embryos.’
Last year a study identified an enzyme used by sperm to get inside the egg and sparked the researcher’s work.
From vasectomies to the male contraceptive pill, there have been many attempts to shift the burden of birth control burden onto men.
In January, a German entrepreneur said he had the solution – a ‘switch’ to stop sperm from reaching the penis.
The valve – which is implanted internally – is designed to divert the flow of sperm back to the man’s testicles, making him temporarily infertile.
If he later decides he wants to become a father, he simply locates the implant in his scrotum and flicks the switch back, allowing sperm to be ejaculated.
Clemens Bimek, the inventor, claims the spermatic duct valve has the potential to ‘change the world’ by offering a contraceptive that is as effective as a vasectomy – without being permanent.
Mr Bimek, a joiner who lives in Berlin, had been watching a documentary on contraception when he had the brainwave.
He is so far the only recipient of the device – which he hopes to fund through £3.8million of investment including crowdfunding – with a trial involving 25 men set to starting this year.