Tomboys likely to become lesbian

It is known that there are well-established traits which differ between girls and boys. For example, boys engage in more 'rough and tumble' play than girls do.

However, a new study by the Queen Mary University in London has found that children who later become gay or lesbian are more likely to steer away from expected gender traits.

Prior studies have shown that between 50 to 80 percent of gender non-conforming boys become gay, and around a third of non-conforming girls become lesbian.

In the current study, psychologists Andrea Burri and Qazi Rahman report that in girls, genes may be partially responsible for gender non-conformity and, by association, sexual orientation.

They followed a group of 4,000 female twins, asking them about their sexual attractions and gender non-conformity.

They discovered genetic influences on sexual orientation (25 percent) and childhood gender nonconformity (31 percent).

"We found that there is a connection between these mental traits and how sexual orientation develops. This is because they all develop under common biological drivers; like the development of brain regions under the influence of genes and sex hormones," the Daily Mail quoted Rahman as saying.

"We think environmental factors and genetics drive other mechanisms, like exposure to sex hormones in the womb, to shape differences in gender nonconformity and sexuality simultaneously," he said.

Rahman is mindful that the results may carry the risk of stereotyping.

"Stereotypes like 'sissy' or 'mannish' have not been helpful in promoting respect for gay people, and those who don't match those stereotypes may find it hard to accept that they are gay or lesbian," Rahman added.

The study is published in PLoS One.