Search results
Results From The WOW.Com Content Network
Identical twin studies are a useful mechanism for assessing the role of genes and environment. Twin studies have also found that among twins with differing sexual orientations, homosexual twins were significantly more gender nonconforming than their heterosexual co-twin, and that this was noticeable from a young age. [29] Bailey states:
Of the pairs of identical twins in which one twin is homosexual, the other twin, despite having the same genome, only has a 20-50% chance of being homosexual as well. [12] This leads to the hypothesis that homosexuality is created by something else rather than the genes.
Bailey carried out early twin studies on homosexuality, finding higher rates of concordance for sexual orientation in identical twins than fraternal twins, suggesting genes or shared prenatal environment have influence on sexual orientation. [17]: 88 Bailey has argued that male sexual orientation appears unaffected by socialization.
The fraternal birth order effect has been described by one of its proponents as "the most consistent biodemographic correlate of sexual orientation in men". [5] In 1958, it was reported that homosexual men tend to have a greater number of older siblings (i.e., a 'later/higher birth order') than comparable heterosexual men and in 1962, these findings were published in detail. [6]
A twin study compares the concordance rate of identical twins to that of fraternal twins. This can help suggest whether a disease or a certain trait has a genetic cause. [3] Controversial uses of twin data have looked at concordance rates for homosexuality and intelligence. Other studies have involved looking at the genetic and environmental ...
Dissection studies found that gay men had significantly smaller sized INAH-3 than heterosexual males, which is shifted in the female typical direction, a finding first demonstrated by neuroscientist Simon LeVay, which has been replicated. [19] Dissection studies are rare, however, due to lack of funding and brain samples. [6]
Image credits: Dr.Bahman Guyuron/American Society of Plastic Surgeons This effect was visible in identical twins Brenda and Barb, who were 52 at the time of the study. “I love being called the ...
Despite numerous attempts, no "gay gene" has been identified. However, there is substantial evidence for a genetic basis of homosexuality, especially in males, based on twin studies; some association with regions of Chromosome 8, the Xq28 locus on the X chromosome, and other sites across many chromosomes. [172