http://news.bbc.co.uk/1/hi/health/4215427.stm
Last Updated: Monday, 31 January, 2005, 00:00 GMT
Multiple genes - and not just the sex chromosomes - are important in sexual orientation, say US scientists.
A University of Illinois team, which has screened the entire human genome, say there is no one 'gay' gene.
Writing in the journal Human Genetics, they said environmental factors are also likely to be involved.
