Scientists say that an on-demand and non-hormonal male contraceptive pill may be on the horizon after successful trials stopped sperm from being able to swim.
The tests in mice suggest keeping the sperm stunned for a few hours, long enough to stop them from reaching the egg.
However, despite this breakthrough, many more tests will be needed before such a product reaches humans, with rabbits the next group to be tested on.
What makes a male contraceptive pill different to a female one?
Male contraceptive pills, unlike female ones, would not involve any hormones.
According to scientists, this has the advantage of not interfering with testosterone and should not cause any male hormone deficiency side effects.
Instead of targeting the "sperm-swim" switch, scientists are targeting a cellular signalling protein called soluble adenylyl cyclase or sAC, inhibiting it.
An early study in mice, funded by the National Institute of Health in the United States, found that a single dose of the drug (which is called TDI-11861) immobilised the sperm.
This effect was reported to have lasted around three hours with this fully wearing off in around 24 hours.
Scientists say new male contraceptive pill shows promise
One of the scientists said the pills showed great promise as a reversible and easy-to-use contraceptive.
Dr Melanie Balbach added that if its does work in humans, men might be able to take it only as often as it is needed.
However, it was noted that this would not protect from sexually transmitted diseases with more traditional contraceptive devices like condoms still being needed.
Prof Allan Pacey, professor of andrology at the University of Sheffield told the BBC: "There is a pressing need for an effective, reversible, oral contraceptive for men and although many different approaches have been tested over the years, none has yet reached the market.
"The approach described here, to knock out key enzyme in sperm that is critical for sperm movement, is a really novel idea. The fact that it is able to act, and be reversed, so quickly is really quite exciting.
"If the trials on mice can be replicated in humans with the same degree of efficacy, then this could well be the male contraceptive approach we have been looking for."
