A recent study of 409 gay brothers suggests that gay people are born that way, according to researchers.
The study appeared in the online edition of Psychological Medicine Nov. 17 and was led by Alan Sanders of NorthShore University HealthSystem Research Institute in Evanston. Among the co-authors of the study was Northwestern University's J. Michael Bailey, whose research on the transgender and gay communities, along with his teaching methods, has drawn strong criticism in the past.
Sanders and his co-authors say they have clearer evidence that genes along two chromosomesthe X chromosome and chromosome 8exert influence over sexual orientation.
Sanders told New Scientist Nov. 17 that their finding "erodes the notion that sexual orientation is a choice," while emphasizing that a specific "gay gene" had not been located.
Scientists have been inquiring about those particular chromosomes since 1993, but this study has contained the largest number of subjects, thus producing the most robust results seen so far. The only trait shared by each subject was being gay.
Sanders also stressed that the presence of the gene only meant a possible predisposition towards being gay, and that individual characteristics are often determined by a combination of environmental and genetic factors.