London: Boys will be boys and engage in more `rough and tumble` play than girls. But a new study blames a set of genes for one`s gay or lesbian tendencies.
Research shows that between 50 to 80 percent of gender nonconforming boys become gays, and about one-third of such girls become lesbians.
Andrea Burri and Qazi Rahman from the Queen Mary`s School of Biological and Chemical Sciences, London, report that a set of genes and a set of random environmental factors are partly responsible both for gay and lesbian orientation, the journal Public Library of Science reports.
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 attraction and behaviour, and a series of follow up questions about their gender nonconformity, according to a Queen Mary statement.
Study co-author Rahman 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."
Rahman adds: "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."
Rahman is mindful that the results may carry the risk of stereotyping, adding: "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 they are gay or lesbian."