Sunday, June 29, 2008

TWINS STUDY: HOMOSEXUALITY SHAPED BY GENES, RANDOM ENVIRONMENTAL FACTORS

SCIENTIFIC BLOGGING Homosexual behavior is largely shaped by genetics and random environmental factors, according to findings from the world's largest study of twins. Researchers from Queen Mary's School of Biological and Chemical Sciences and Karolinska Institutet in Stockholm report in the Archives of Sexual Behavior 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 behavior. . .

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 behavior is also influenced by a mixture of genetic and environmental factors. . .

"Overall, genetics accounted for around 35 per cent of the differences between men in homosexual behaviour and other individual-specific environmental factors (that is, not societal attitudes, family or parenting which are shared by twins) accounted for around 64 per cent. In other words, men become gay or straight because of different developmental pathways, not just one pathway."

For women, genetics explained roughly 18 per cent of the variation in same-sex behavior, non-shared environment roughly 64 per cent and shared factors, or the family environment, explained 16 per cent.

The study shows that genetic influences are important but modest, and that non-shared environmental factors, which may include factors operating during foetal development, dominate. Importantly, heredity had roughly the same influence as shared environmental factors in women, whereas the latter had no impact on sexual behavior in men.

Dr Rahman adds: "The study is not without its limitations - we used a behavioral measure of sexual orientation which might be OK to use for men (men's psychological orientation, sexual behaviour, and sexual responses are highly related) but less so for women (who show a clearer separation between these elements of sexuality). Despite this, our study provides the most unbiased estimates presented so far of genetic and non-genetic contributions to sexual orientation."

2 Comments:

At June 29, 2008 5:55 PM, Anonymous Anonymous said...

Fine, but let's focus on the real problem: what causes homophobia?

 
At June 30, 2008 8:55 AM, Anonymous Anonymous said...

That's easy to answer. It's the practice of allowing parents to brainwash their children into believing a long list of nonsense when they're too young to think for themselves: Santa Claus, the Easter Bunny, the Tooth Fairy, God, Jesus, creationism, sexism, racism, homophobia, classism, weightism, astrology, capitalism etc. The first things children need to be taught are critical thinking, science, math, and how to recognize propaganda.

 

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