Navigation Links
Homosexual behavior due to genetics and environmental factors
Date:6/28/2008

Homosexual behaviour is largely shaped by genetics and random environmental factors, according to findings from the world's largest study of twins.

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.

The team led by Dr Niklas Lngstrm at Karolinska Institutet conducted the first truly population-based survey of all adult (20-47 years old) twins in Sweden. Studies of identical twins and non-identical, or fraternal, twins are often used to untangle the genetic and environmental factors responsible for a trait. While identical twins share all of their genes and their entire environment, fraternal twins share only half of their genes and their entire environment. Therefore, greater similarity in a trait between identical twins compared to fraternal twins shows that genetic factors are partly responsible for the trait.

This study looked at 3,826 same-gender twin pairs (7,652 individuals), who were asked about the total numbers of opposite sex and same sex partners they had ever had. The findings showed that 35 per cent of the differences between men in same-sex behaviour (that is, that some men have no same sex partners, and some have one or more) is accounted for by genetics. Rahman explains:

"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 behaviour, 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 behaviour in men.

Dr Rahman adds: "The study is not without its limitations - we used a behavioural 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."


'/>"/>

Contact: Sian Halkyard
s.halkyard@qmul.ac.uk
07-970-096-175
Queen Mary, University of London
Source:Eurekalert

Related medicine news :

1. Atchison receives Behavioral, Epidemiological and Health Services Research Award
2. Binge drinking due to copying behavior
3. Behavioral Risk in the Workplace: Behavioral Risk Management Continues to be an Important Best Practice Area for Employers
4. Integrated Behavioral Health Optimizes Claims Processing With BlueThreads SmartDesk, K2 Workflow and Microsoft Office SharePoint Server
5. Brain Activity May Predict Schizophrenia Behavior
6. Improving understanding of cell behavior in breast cancer
7. Children learn smart behaviors without knowing what they know
8. Insomnia in parents can result in sleep problems, suicidal behavior among their offspring
9. Poor sleep linked to suicidal behavior among children and adolescents with depressive episodes
10. Frequent self-cutting linked to risky sexual behavior in teens
11. Adding Light Eases Behavioral Problems of Dementia
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/26/2016)... ... 26, 2016 , ... PawPaws brand pet supplements owned by Whole ... enhance the health of felines. The formula is all-natural and is made from Chinese ... PawPaws Cat Kidney Support Supplement Soft Chews are Astragalus Root Extract and ...
(Date:6/25/2016)... FL (PRWEB) , ... June 25, 2016 , ... The temporary closing of Bruton Memorial ... Plant City Observer , brings up a new, often overlooked aspect of head lice: the ... closing for fumigation is not a common occurrence, but a necessary one in the event ...
(Date:6/25/2016)... ... June 25, 2016 , ... On Friday, June 10, Van Mitchell, Secretary ... Work award to iHire in recognition of their exemplary accomplishments in worksite health promotion. ... Maryland Workplace Health & Wellness Symposium at the BWI Marriott in Linthicum Heights. iHire ...
(Date:6/24/2016)... ... June 24, 2016 , ... Marcy was in a crisis. Her son James, eight, was ... his family verbally and physically. , “When something upset him, he couldn’t control his emotions,” ... He would throw rocks at my other children and say he was going to kill ...
(Date:6/24/2016)... ... ... of Topricin and MyPainAway Pain Relief Products, join The ‘Business for a Fair Minimum Wage’ ... 2020 and then adjusting it yearly to increase at the same rate as the median ... floor does not erode again, and make future increases more predictable. , The company is ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... , June 24, 2016  Collagen Matrix, ... design, development and manufacturing of collagen and mineral ... announced today that Bill Messer has ... Marketing to further leverage the growing portfolio of ... devices. Bill joins the Collagen Matrix ...
(Date:6/24/2016)... , June 24, 2016 ... Markets has announced the addition of the " ... offering. This ... and provides an updated review, including its applications in ... the total market, which includes three main industries: pharmaceutical ...
(Date:6/24/2016)... BEIJING , June 24, 2016 Dehaier ... or the "Company"), which develops, markets and sells medical ... China , signed a strategic cooperation agreement with ... as "Hongyuan Supply Chain") on June 20, 2016, to ... Under the strategic cooperation agreement, Dehaier will leverage Hongyuan ...
Breaking Medicine Technology: