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)... Michigan (PRWEB) , ... June 26, 2016 , ... On ... as sponsor of the 2016 Cereal Festival and World’s Longest Breakfast Table in Battle ... honor of the city’s history as home to some of the world’s leading providers ...
(Date:6/25/2016)... ... 2016 , ... Experts from the American Institutes for Research ... June 26-28, 2016, at the Hynes Convention Center in Boston. , AIR experts ... planning, healthcare costs and patient and family engagement. , AIR researchers will be ...
(Date:6/25/2016)... ... June 25, 2016 , ... As a lifelong Southern Californian, Dr. Omkar ... M.D from the David Geffen School of Medicine at UCLA. He trained in Internal ... complete his fellowship in hematology/oncology at the UCLA-Olive View-Cedars Sinai program where he had ...
(Date:6/24/2016)... ... June 24, 2016 , ... Those who have experienced traumatic events ... turn to unhealthy avenues, such as drug or alcohol abuse, as a coping mechanism. ... tools for healthy coping following a traumatic event. , Trauma sufferers tend to feel ...
(Date:6/24/2016)... ... June 24, 2016 , ... Dr. Amanda Cheng, ... treatment. Dr. Cheng has extensive experience with all areas of orthodontics, including robotic ... osteogenic orthodontics. , Micro-osteoperforation is a revolutionary adjunct to orthodontic treatment. It ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... Research and Markets has announced the addition of ... their offering. The current ... environment for MedImmune to enter. The US ageing population creates ... drive considerable growth for effective anti-influenza medications. The introduction of ... but development is still in its infancy. ...
(Date:6/23/2016)... and INDIANAPOLIS , June 23, ... a Lilly Diabetes Tomorrow,s Leaders Scholarship is any indication, ... winners, announced today online at www.diabetesscholars.org by ... 1 diabetes stand in the way of academic and ... the Foundation,s scholarship program since 2012, and continues to ...
(Date:6/23/2016)...  Guerbet announced today that it has been named ... . One of 12 suppliers to receive ... support of Premier members through exceptional local customer service ... to lower costs. ... outstanding customer service from Premier," says Massimo Carrara ...
Breaking Medicine Technology: