Human development Sexual orientation Sibling. New York Magazine. In a study, its authors stated that "There is considerable evidence that human sexual orientation is genetically influenced, so it is not known how homosexuality, which tends to lower reproductive success, is maintained in the population at a relatively high frequency. Archives of General Psychiatry. Therefore, any SNPs consistently found in the same genetic locations across the group would most likely be associated with sexual orientation. Michael; Martin, Eden R.
Three studies have investigated whether sexual orientation also correlates with fraternal birth order in men attracted to physically immature males.
LGBT culture. One of the women had died of an AIDS-related illness. The Royal College of Psychiatrists. This is because the effect is present regardless of whether or not the older brothers are raised in the same family environment with the boy.
Implications for the Kin Selection Hypothesis".