Further Evidence Genetics Has Role in Determining Sexual Orientation in Men
Canadian scientists have uncovered new evidence which shows genetics has a role to play in determining whether an individual is homosexual or heterosexual.
The research was conducted by Dr. Sandra Witelson, a neuroscientist in the Michael G. DeGroote School of Medicine at McMaster University, and colleagues at Sunnybrook Health Sciences Centre in Toronto who studied the brains of healthy, right-handed, 18- to 35-year-old homosexual and heterosexual men using structural Magnetic Resonance Imaging (MRI).
About 10 years ago, Witelson and Dr. Cheryl McCormick, then a student of Witelson’s, demonstrated there is a higher proportion of left-handers in the homosexual population than in the general population – a result replicated in subsequent studies which is now accepted as fact.
Handedness is a sign of how the brain is organized to represent different aspects of intelligence. Language, for example, is usually on the left - music on the right.
In other research, Witelson and research associate Debra Kigar, had found that left-handers have a larger region of the posterior corpus callosum – the thick band of nerve fibers connecting the two hemispheres of the brain – than right handers.
This raised the hypothesis for the current study – whether the anatomy of the brain of the sub-group of right-handed homosexual men is similar to that of left-handers.
They found that the posterior part of the corpus callosum is larger in homosexual than heterosexual men.
The size of the corpus callosum is largely inherited suggesting a genetic factor in sexual orientation, says Witelson. “Our results do not mean that heredity is destiny but they do indicate that environment is not the only player in the field,” she says.
While this is not a litmus test for sexual orientation, Witelson said this finding could prove to be one additional valuable piece of information for physicians and individuals who are trying to determine their sexual orientation. “Sometimes people aren’t sure of their sexual orientation.”
Watch more breaking news now on our video feed:
Bookmark http://universeeverything.blogspot.com/ and drop back in sometime.
The research was conducted by Dr. Sandra Witelson, a neuroscientist in the Michael G. DeGroote School of Medicine at McMaster University, and colleagues at Sunnybrook Health Sciences Centre in Toronto who studied the brains of healthy, right-handed, 18- to 35-year-old homosexual and heterosexual men using structural Magnetic Resonance Imaging (MRI).
About 10 years ago, Witelson and Dr. Cheryl McCormick, then a student of Witelson’s, demonstrated there is a higher proportion of left-handers in the homosexual population than in the general population – a result replicated in subsequent studies which is now accepted as fact.
Handedness is a sign of how the brain is organized to represent different aspects of intelligence. Language, for example, is usually on the left - music on the right.
In other research, Witelson and research associate Debra Kigar, had found that left-handers have a larger region of the posterior corpus callosum – the thick band of nerve fibers connecting the two hemispheres of the brain – than right handers.
This raised the hypothesis for the current study – whether the anatomy of the brain of the sub-group of right-handed homosexual men is similar to that of left-handers.
They found that the posterior part of the corpus callosum is larger in homosexual than heterosexual men.
The size of the corpus callosum is largely inherited suggesting a genetic factor in sexual orientation, says Witelson. “Our results do not mean that heredity is destiny but they do indicate that environment is not the only player in the field,” she says.
While this is not a litmus test for sexual orientation, Witelson said this finding could prove to be one additional valuable piece of information for physicians and individuals who are trying to determine their sexual orientation. “Sometimes people aren’t sure of their sexual orientation.”
Watch more breaking news now on our video feed:
Bookmark http://universeeverything.blogspot.com/ and drop back in sometime.
Labels: brain, gay, genetics, homosexual, men, sexual orientation
posted by Scott Nance at
11/07/2007 09:34:00 PM
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