While the original title of the article below gives the impression that genetics plays an equal or even greater influence than environment, the study in fact shows that genetics is only 35% for men and 18% for women.
-- From "Homosexual Behavior Largely Shaped by Genetics and Random Environmental Factors" from ScienceDaily.com, 6/30/08
Writing in the scientific journal Archives of Sexual Behavior, researchers from Queen Mary's School of Biological and Chemical Sciences, and Karolinska Institutet in Stockholm report that genetics and environmental factors (which are specific to an individual, and may include biological processes such as different hormone exposure in the womb), are important determinants of homosexual behaviour.
Dr Qazi Rahman, study co-author and a leading scientist on human sexual orientation, explains: "This study puts cold water on any concerns that we are looking for a single 'gay gene' or a single environmental variable which could be used to 'select out' homosexuality - the factors which influence sexual orientation are complex. And we are not simply talking about homosexuality here - heterosexual behaviour is also influenced by a mixture of genetic and environmental factors.
Like gambling, alcoholism, obesity, and even religiosity, political views, and (!) violence, current science holds that homosexuality has a genetic component (from 1/3 to 1/5 of the story). Regardless of the breakdown of genetics vs. environment, we ought to think and act in ways that may sometimes go against our natural inclinations.