It may be possible to develop a new male contraceptive pill after researchers in Edinburgh identified a gene critical for the production of healthy sperm.
Experiments in mice found that the gene, Katnal1, was vital for the final stages of making sperm.
The authors of a study in PLos Genetics said a drug which interrupts Katnal1 could be a reversible contraceptive.
A fertility expert said there was “certainly a need” for such a drug.
Contraception in men is largely down to condoms or a vasectomy.