The study undertaken by Harvard and MIT researches, published in Science, used data from the UK Biobank and 23andMe, and found some genetic variants associated with same-sex relationships. Five specific genetic variants were found to be particularly associated with same-sex behaviour. Together they only accounted for under 1% of samesex behaviour. The researchers scanned the entire genetic make-up of 409,000 people. Participants were asked whether they had same-sex partners exclusively, or as well as opposite-sex partners.