Twins and sexual orientation and genes

But this argument has never been substantiated, despite the fact that studies have shown that homosexuality is a heritable trait. This can shed light on a possible genetic cause. Gay men and straight women have, on average, equally proportioned brain hemispheres. And scientific evidence shows their parents cannot be blamed. Those mice who retained the gene fucose mutarotase FucM were attracted to male mice. Gay brothers who showed this maternal pedigree were then tested for X chromosome linkage, using twenty-two markers on the X chromosome to test for similar alleles. Female fertility[ edit ] In , Italian researchers conducted a study of about 4, people who were the relatives of 98 homosexual and heterosexual men.

The heterosexual advantage hypothesis was given strong support by the Italian study demonstrating increased fecundity in the female matrilineal relatives of gay men. Your email format is wrong! In identical twins, DNA is shared and overlaps perfectly. The work was conducted in conjunction with the Ugandan Academy of Science. The early fixation hypothesis includes research into prenatal development and the environmental factors that control masculinization of the brain. The Science of Desire: In 10 of the pairs studied, both twins identified as homosexual.

I realise these two are twins but children of the same parents are not always brought up in the same way. But what does the science say? Home News Sport Business. I do think we have more of a say in our sexual behavior than these studies suggest, but I don't have much tolerance for anyone willing to place moral judgments on folks for homosexuality.