Thursday, Nov. 8

For years scientists have debated if sexual orientation is determined by nature or nurture. New evidence suggests genetics is a significant factor for whether an individual is homosexual or heterosexual. The findings emanate from a Canadian study of the brains of healthy, right-handed, 18- to 35-year-old homosexual and heterosexual men using structural Magnetic Resonance Imaging (MRI).

The size of the corpus callosum is largely inherited suggesting a genetic factor in sexual orientation, said Witelson

The researchers also undertook a correlational analysis which included size of the corpus callosum, and test scores scores on language, visual spatial and finger dexterity tests. “By using all these variables, we were able to predict sexual orientation in 95 per cent of the cases,” she said.