A contraceptive pill for men that works by causing temporary infertility could eventually become available in the UK.
Scientists said that blocking or deactivating the Arrdc5 gene, which is responsible for producing sperm, could form the basis of a reversible male contraceptive treatment.
Researchers at Washington State University used mice to test the impact of deactivating the gene on fertility.
They found that the mice produced 28 per cent less sperm compared to their normal counterparts. The sperm travelled at a third of the speed and came out in abnormal shapes.
Professor Jon Oatley, one of the study’s authors, said: “The study identifies this gene for the first time as being expressed only in testicular tissue, nowhere else in the body.
“When this gene is inactivated or inhibited in males they make sperm that cannot fertilise an egg, and that’s a prime target for male contraceptive development.”
The team said that the treatment would not impact male hormones. A contraceptive pill for women has been available for over 60 years.
Prof Oatley added: “You don’t want to wipe out the ability to ever make sperm - just stop the sperm that are being made from being made correctly.
“Then, in theory, you could remove the drug and the sperm would start being built normally again.”
Researchers are currently working on a drug for humans which can block the protein made by Arrdc5. The gene is specific to the male testes and found in multiple species.
Professor Richard Anderson, of the University of Edinburgh, who was not part of the study, said: “The last couple of years has seen a very encouraging uptick in really promising new targets for a ‘male pill’. This study identifies a novel gene which clearly has a major role in sperm production.
“Sperm production was low, those sperm that were produced didn’t function, and the male mice were completely infertile, but otherwise healthy. So [it’s] very interesting.”
At present, the only available male contraceptives are condoms or a vasectomy.
However, a study by the US National Institutes of Health has shown promising results for Nestorone hormone gel, which can be rubbed into the skin to lower sperm count.
The study was published on Monday in the journal Nature Communications.
