Scientists at Queen Mary, University of London, say they've found evidence that women's sexual orientation and their tendency to conform to gender roles are both genetic traits. Essentially, the finding is that women who developed with the same set of environmental and genetic factors were more likely to have the same sexual orientation and attitudes toward gender roles. Science Daily has the story:
The team followed a group of 4,000 British women who were one of a pair of twins. They were asked questions about their sexual attractions and behaviour, and a series of follow up questions about their gender nonconformity. In line with previous research, the team found modest genetic influences on sexual orientation (25 per cent) and childhood gender nonconformity (31 per cent).
Dr Qazi Rahman, co-author of the study, explains: "We found that there is a connection between these mental traits and how sexual orientation develops. One idea is that there is an association between these psychological traits and sexual orientation because they all develop under common biological drivers; like the development of brain regions under the influence of genes and sex hormones."
Why does this matter? Well, Rahman points to the mental well-being of lesbian and gender non-conforming women, for a start: "Poor mental health in gay populations is partly due to societal stigma and victimisation. Our results suggest that being gender nonconforming and lesbian comes from 'within'; there is little you can do about it. So gender nonconformity does not cause mental health problems, but it may trigger negative reactions from other people (like parents and peers), leading to mental health problems."