The Gay Brain? Neuroscientists find evidence that homosexuality is hard-wired
The Proceedings of the National Academy of Sciences (PNAS) published an interesting article in today’s journal that examines the physical structure of brains in heterosexual and homosexual study participants.
The best summary of the article, PET and MRI show differences in cerebral asymmetry and functional connectivity between homo- and heterosexual subjects, authored by lead researchers Ivanka Savic and Per Linstrom of the Stockholm Brain Institute in Sweden, is provided by Richard Monastersky on the Chronicle of Higher Education‘s News Blog:
Is There a Gay Brain? Imagine Study Finds Anatomical Clues
[Neuroscience researchers] found that the brains of homosexual men and heterosexual women were more symmetrical than the brains of heterosexual men and homosexual women. A similar difference emerged when the researchers looked in particular at the amygdala, a brain region associated with emotional reactions. Heterosexual women and homosexual men had more connections between their right and left amygdala and more connections with other brain regions than did homosexual women and heterosexual men.
Scientists have spent decades looking for brain differences between homosexual and heterosexual people and since the early 1990s have been finding anatomical distinctions in regions associated with sexual behavior. The new study suggests broader brain differences between homosexual and heterosexual men and women, even in regions not linked to sexual attraction.
The BBC article where I first read of this study can be found here.
In 2005, Dr. Savic was the lead researcher on another neuroscientific investigation about the “gay brain.” The title of that article, also published by PNAS, is Brain response to putative phermones in homosexual men.
In this 2005 study, it was discovered — as the title of the article says — that “the brains of homosexual men respond more like those of women when reacting to a chemical derived from the male sex hormone.” [Source]
These two studies lend evidence to the debate over whether sexual orientation is a biologically-determined trait.
Entry filed under: think. Tags: amygdale, anatomical distinctions, assymetry, biologically determined, brain differences, cerebral assymetry, functional connectivity, gay brain, heterosexual brain, homosexual brain, Ivanka Savic, LGBT, MRI, neurobiology, neuroscience, Per Linstrum, PET, phermones, PNAS, Richard Monastersky, sex differences, Stockholm Brain Institute, Sweden.