A study at the Karolinska Institute in Stockholm has provided strong evidence that sexuality is a biologically fixed trait demonstrated in physical brain differences, New Scientist reports.
Specifically, key brain structures in homosexuals which govern "mood, anxiety and aggressiveness" resemble those in heterosexuals of the opposite sex - something likely to have been "forged" in the womb and not the result of later learning processes.
Savic and Lindström put a group of 90 volunteers through the MRI scanner - 25 heterosexuals and 20 homosexuals of each gender - to determine their overall brain shape and volume. The results showed that straight chaps boasted asymmetric brains, "with the right hemisphere slightly larger", something they shared with lesbians.
Gay men, however, demonstrated symmetrical brains, in common with straight women.
In straight men and lesbians, the amygdala sends signals "mainly into the sensorimotor cortex and the striatum, regions of the brain that trigger the 'fight or flight' response". For gay men and straight women, meanwhile, "the connections were mainly into regions of the brain that manifest fear as intense anxiety".
Ivanka Savic of the Karolinska Institute and her colleague Per Lindstrom first used magnetic resonance imaging, or MRI, to compare the symmetry of the brains of 25 straight men and 25 straight women with those of 20 gay men and 20 gay women.
Gay men tended to have brains that were more like those of straight women than of straight men -- the right and left sides were about the same size, the researchers found. Gay women's brains tended to be more like those of straight men than of straight women -- the right side tended to be slightly larger than the left.
To address this question, 80 homosexual and heterosexual men and women (16 homosexual men and 15 homosexual women) underwent structural MRI. We used voxel-based morphometry to test for differences in grey matter concentration associated with gender and sexual orientation. Compared with heterosexual women, homosexual women displayed less grey matter bilaterally in the temporo-basal cortex, ventral cerebellum, and left ventral premotor cortex. The relative decrease in grey matter was most prominent in the left perirhinal cortex. The left perirhinal area also showed less grey matter in heterosexual men than in heterosexual women. Thus, in homosexual women, the perirhinal cortex grey matter displayed a more male-like structural pattern.
In 1991, a neuroscientist in San Diego named Simon LeVay told the world he had found a key difference between the brains of homosexual and heterosexual men he studied. LeVay showed that a tiny clump of neurons of the anterior hypothalamus - which is believed to control sexual behavior - was, on average, more than twice the size in heterosexual men as in homosexual men. LeVay's findings did not speak directly to the nature-vs.-nurture debate - the clumps could, theoretically, have changed size because of homosexual behavior. But that seemed unlikely, and the study ended up jump-starting the effort to prove a biological basis for homosexuality.
Later that same year, Boston University psychiatrist Richard Pillard and Northwestern University psychologist J. Michael Bailey announced the results of their study of male twins. They found that, in identical twins, if one twin was gay, the other had about a 50 percent chance of also being gay. For fraternal twins, the rate was about 20 percent. Because identical twins share their entire genetic makeup while fraternal twins share about half, genes were believed to explain the difference. Most reputable studies find the rate of homosexuality in the general population to be 2 to 4 percent, rather than the popular "1 in 10" estimate.
In 1993 came the biggest news: Dean Hamer's discovery of the "gay gene." In fact, Hamer, a Harvard-trained researcher at the National Cancer Institute, hadn't quite put it that boldly or imprecisely. He found that gay brothers shared a specific region of the X chromosome, called Xq28, at a higher rate than gay men shared with their straight brothers. Hamer and others suggested this finding would eventually transform our understanding of sexual orientation.
Originally posted by OnceReturned
S&F, anything to discourage those poor "sexuality is undoubtedly a choice because god said gays are sinners" fools is valuable in my book. But, I suppose those are the people who don't care much for science anyway, so this information is likely to be lost on them.
Originally posted by Hullabaloo
Dean Hamer's discovery of the "gay gene."… Hamer and others suggested this finding would eventually transform our understanding of sexual orientation.
Unfortunately, that hasn’t really happened yet has it? It sickens me when people still in what should be a modern society adopt primitive concepts like, “homosexuality is a choice,” or “homosexuality is a mental disorder,” or “Homosexuality is caused by bad parenting.” These ideas are atrocious and are based on zero evidence… Homosexuality is not a choice …Homosexuality is not bad and no one can get rid of homosexuals
Originally posted by oppaperclip
One group like their sex organs so much they dedicate their lives to getting more of that organ. Straight people like the complementary organ a lot and try to more of it. Bi sexual are just greedy.
It sickens me when people still in what should be a modern society adopt primitive concepts like, “homosexuality is a choice,” or “homosexuality is a mental disorder,” or “Homosexuality is caused by bad parenting.” These ideas are atrocious and are based on zero evidence. Homosexuality is not a choice and homosexuals have been driven to suicide because of such an ignorant accusation.
The banana is about to disappear from store shelves around the globe. Experts say the world's favourite fruit will pass into oblivion within a decade. No more fresh bananas. No more banana bread. No more banana muffins or banana cream pie.
The banana's main problem is that it has become sterile and seedless as a result of 10,000 years of selective breeding