Researchers say that they are close to developing a birth control pill for men.
Scientists at the University of Minnesota College of Pharmacy claim to have made progress by tweaking a compound developed by previous research, according to The Times.
Since the female pill was made available 50 years ago, experts have yet to pause fertility for men without huge side effects.
Research lead Gunda Gerog told The Times: '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," Gerog continued.
Last year a study identified an enzyme used by sperm to get inside the egg which sparked the research work.
John Herr, a professor of cell biology who worked on that study, at the time said: "Understanding at the molecular level exactly how the sperm is able to bind with and enter the egg, opens opportunities to identify molecules that can disrupt or block the fertilisation event," according to the Evening Standard.