Scientists have identified a gene that plays a vital role in the development of sperm.
The gene, Katnal1, is required for sperm to mature in the testes and could therefore be a target for the development of non-hormonal male contraceptives.
This would be a major step forward, as efforts to produce a male contraceptive have so far focused on treatments that disrupt the production of hormones such as testosterone, which can cause unpleasant side-effects.
Dr Lee Smith, from the University of Edinburgh's Centre for Reproductive Health, described the identification of Katnal1 as a 'unique and significant step forward'.
He noted: 'The important thing is that the effects of such a drug would be reversible because Katnal1 only affects sperm cells in the later stages of development, so it would not hinder the early stages of sperm production and the overall ability to produce sperm.'
The findings are published in the journal PLoS Genetics and were welcomed by Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, who said the gene's discovery could have other implications as well.
He told the BBC: 'The gene described by the research group in Edinburgh sounds like an exciting new possible target for a new male contraceptive, but it may also shed light on why some men are sub-fertile and why their sperm does not work properly.'