A new contraceptive pill for men will temporarily stun their sperm, scientists have said. 

The drug has only been tested on mice so far but scientists found that it immobilised sperm for long enough to stop them swimming towards and fertilising an egg. 

The pill will now be tested on rabbits and then on people. 

“It needs to be taken, I believe, three hours before sex and the following day fertility is back to normal,” GP Dr Sinéad Beirne told The Pat Kenny Show.

“It makes the sperm immotile - which makes them ineffective.” 

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Despite this, Dr Beirne was keen to stress that no contraception is 100% effective. 

“The best contraception that we have are these long acting devices,” she said. 

“But I have met patients that have gotten pregnant with coils insitu and we’re had scans done and there is a growing foetus and, right beside it, a contraceptive device happily sitting there. 

“Any maternity hospital will tell you babies are born with these mirenas literally in their hands. 

“So, I’m afraid that the only 100% way is abstinence, in my experience.” 

Pregnant woman sitting on bed

Another key issue is whether many women will trust their partner to take this pill prior to intercourse.

“The consequence of sex when it results in pregnancy [are with] the woman - there’s no denying it,” Dr Beirne said. 

“They’re the one with the consequence.” 

Last year, the Government introduced free contraception for women and girls aged between 17 and 25-years-old.

Main image: A man taking a pill. Picture by: Alamy.com