Born or Bred?
Science Does Not Support the Claim That Homosexuality Is Genetic
Robert Knight
The X Chromosome
Another fact that casts doubt on Hamer's conclusions is that other researchers tried to replicate his study but failed. In 1999, Drs. George Rice, Neil Risch and George Ebers published their findings in Science after attempting to replicate Hamer's Xq28 study. Their conclusion: "We were not able to confirm evidence for an Xq28-linked locus underlying male homosexuality."
Moreover, they added that when another group of researchers (Sanders, et al.) tried to replicate Hamer's study, they too failed to find a genetic connection to homosexuality.
The Twins Study
In 1991, J. Michael Bailey and Richard C. Pillard published a study that examined identical and fraternal twin brothers and adopted brothers in an effort to establish a genetic link to homosexuality. Fifty-two percent of the identical twins were reportedly homosexual, while only 22 percent of fraternal twins fell into the same category. But since identical twins have identical genetic material, the fact that nearly half of the identical twins were heterosexual effectively refutes the idea that homosexuality has a genetic basis.
Bailey conducted another study in 1999, published in the March 2000 issue of the Journal of Personality and Social Psychology, which actually showed less possible genetic influence on homosexuality than the first twins study. He sent a questionnaire to the entire Australian Twin Registry. Only three pairs of identical male twins were both homosexual out of a total of 27 in which at least one was homosexual. Of the 16 fraternal male twins, none of the pairs was both homosexual. Bailey found similar results for lesbians.
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