Twin studies[ edit ] A number of twin studies have attempted to compare the relative importance of genetics and environment in the determination of sexual orientation.
This article is over 4 years old Boy Scouts at a gay pride parade in Seattle. Scientists tested the DNA of gay men and found that genes on at least two chromosomes affected whether a man was gay or straight.
A region of the X chromosome called Xq28 had some impact on men's sexual behaviour — though scientists have no idea which of the many genes in the region are involved, nor how many lie elsewhere in the genome. Another stretch of DNA on chromosome 8 also played a role in male sexual orientation — though again the precise mechanism is unclear.
Researchers have speculated in the past that genes linked to homosexuality in men may have survived evolution because they happened to make women who carried them more fertile. This may be the case for genes in the Xq28 region, as the X chromosome is passed down to men exclusively from their mothers.
Michael Bailey, a psychologist at Northwestern University in Illinois, set out the findings at a discussion event held in conjunction with the annual meeting of the American Association for the Advancement of Science in Chicago on Thursday.
The work has yet to be published, but confirms the findings of a smaller study that sparked widespread controversy inwhen Dean Hamer, a scientist at the US National Cancer Institute, investigated the family histories of more than gay men and found homosexuality tended to be inherited.
Uncles and male cousins on the mother's side had a greater than average chance of being gay, too. The link with the mother's side of the family led Hamer to look more closely at the X chromosome. In follow-up work, he found that 33 out of 40 gay brothers inherited similar genetic markers on the Xq28 region of the X chromosome, suggesting key genes resided there.
Hamer faced a firestorm when his study was published. The fuss centred on the influences of nature and nurture on sexual orientation. But the work also raised the more dubious prospect of a prenatal test for sexual orientation.
Hamer warned that any attempt to develop a test for homosexuality would be "wrong, unethical and a terrible abuse of research". The gene or genes in the Xq28 region that influence sexual orientation have a limited and variable impact. Not all of the gay men in Bailey's study inherited the same Xq28 region.
The genes were neither sufficient, nor necessary, to make any of the men gay. The flawed thinking behind a genetic test for sexual orientation is clear from studies of twins, which show that the identical twin of a gay man, who carries an exact replica of his brother's DNA, is more likely to be straight than gay.
That means even a perfect genetic test that picked up every gene linked to sexual orientation would still be less effective than flipping a coin. While genes do contribute to sexual orientation, other multiple factors play a greater role, perhaps including the levels of hormones a baby is exposed to in the womb.
But it is not completely determinative; there are certainly other environmental factors involved. Whatever gene contributes to sexual orientation, you can think of it as much as contributing to heterosexuality as much as you can think of it contributing to homosexuality.
It contributes to a variation in the trait. All human psychological traits are heritable, that is, they have a genetic component," he said.
However, we don't know where these genetic factors are located in the genome. So we need to do 'gene finding' studies, like this one by Sanders, Bailey and others, to have a better idea where potential genes for sexual orientation may lie.
Historically, the persecution and awful treatment of LGBT groups has been because politicians, religious leaders and societies have viewed sexual orientation as 'choice' or due to poor upbringing.It finds that epigenetic effects, chemical modifications of the human genome that alter gene activity without changing the DNA sequence, may have a major influence on sexual orientation.
Dec 24, · A list of studies doesn't prove anything. Click to expand Then why did you suggest references be posted in the first place? Moreover, non-biased references are bound to receive more respect. My point is - if you are making a claim, then back up that point with a credible source.
Click to. Aug 07, · The Causes Of Homosexuality Discussion in 'Non-denominational' started by waves, Jul 23, Page 1 of 2 1 2 Next > Jul Gay men are no more likely to have been sexually abused as a child than straight men.
and for both it is something that happens to just a small percentage. the same holds true of women. regardless of their sexual.
And the author says, "If sexual preference can be altered, then people who support gay rights can’t rely on the argument that gay people should be protected from discrimination because gay people have no choice but to be gay – an argument that seems like an apology for homosexuality, as if homosexuality is a disease for which there is no cure.".
Science Does Not Support the Claim That Homosexuality Is Genetic homosexuality has a genetic or hormonal cause. A handful of studies, none of them replicated 8 Robert L.
Spitzer, “Can Some Gay Men and Lesbians Change Their Sexual Orientation?”, Archives of Sexual Behavior, Vol. 32, No. 5, October Genesis of Homosexuality. How does a person become gay? Is it genetic?
Is it a learned behavior? Or perhaps it is a mixture of the two? In order to solve this puzzle, let us look at five major studies performed by non-Christian, secular scientists on the biological origin of sexual orientation.