| ‘Gay gene’ debunked |
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Rachel Cook
Scientists who have carried out the world’s largest study involving twins, both identical and fraternal, have found that homosexuality is the result of random environmental factors and genetics.
The research, which looked at 3,826
same-gender twin pairs, was conducted by the Queen Mary’s “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,” said Dr Qazi Rahman, the studies co-author, in a media release. Researchers looked at three areas of possible influence on sexual orientation: genetics, shared environment (common to identical and fraternal twins), and individual-specific environment factors, which may include factors operating during foetal development. The study found that genetics account for 35 percent of sexual orientation in men and 18 percent in women, while individual-specific environmental factors accounted for 64 percent in both men and women. Shared environment factors explained 16 percent of the variation in same-sex behaviour in women. “The study shows that genetic influences are important but modest, and that non-shared environmental factors dominate,” Rahman said.
The study is somewhat
supportive of the Australian Christian Lobby’s (ACL) view that homosexuality is
learnt behaviour. Victorian State Director of the ACL, Rob Ward, told MCV.
“The report confirms
the result of previous twin-based surveys that there is no ‘gay gene’. This has
been and remains our understanding."
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written by Kim Rea , July 04, 2008 Darwinian logic for homosexuality? Robert Kunzig (Psychology Today May/June 2008 p89 published by Sussex Publishers Inc www.PsychologyToday.com) ponders the evolutionary mystery of homosexuality and asks why such an evolutionary disadvantage was not selected into oblivion millennia ago. Biologists are now suggesting homosexuality is the outcome of sexually antagonistic selection. Mothers trigger a genetic switch to feminize men into becoming kinder, gentler and more nurturing so as to help raise children rather than kill them or each another. Flip the switch too far and your gentle man goes gay. Researchers have discovered mothers and aunts of gay men: •had fewer miscarriages and fewer infections; and •had between 3 and 4 times as many sexual partners. The biological theory is that mothers’ sexual appetite gene is passed onto their sons but it transfers to some of their sons as a sexual appetite for men. However, Kunzig says researchers concede this is just a theory and 70% or more of homosexual orientation may have other causes. Other research conclusions identified by Kunzig include: •older biological brothers increase the prospect of the youngest right-handed brother being gay (even though first-borns can be gay too) •left-handed men are more likely to be gay irrespective of the sex of their siblings •only 2% to 6% of men are gay •not enough research has been done to clarify the application of these theories to lesbianism. Kunzig’s article is entitled Finding the Switch which raises its own questions: if biologists do find THE switch, will we be obliged to turn it off? Would we want to? report abuse
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