Papers in Australia and the UK published stories late yesterday about a study recently described at the 2013 International Association for Sex Research by Alan Sanders and then yesterday by Michael Bailey at the American Association for the Advancement of Science on genetics and homosexuality. According to an abstract of a 2012 presentation of the study, the researchers conducted a genome-wide linkage study involving over 400 pairs of gay brothers. The team identified two regions of interest: the pericentromeric region of chromosome 8 and Xq28, the region previously reported by Dean Hamer in 1993. According to the 2012 abstract, the findings “suggest that genetic variation in each of these regions contributes to development of the important psychological trait of male sexual orientation.”
The study has not been published but will surely renew interest in genetic factors involved in homosexuality. According to Bailey, as reported in the Guardian, sexual orientation is not a choice. However, this does not mean that sexual orientation is completely determined by genes. It appears that the regions identified in this study contribute in some manner to variation in the trait of sexual orientation. The linkages identified in the study do not eliminate the role of other factors in sexual orientation, including the balance of hormones during fetal development.
The new study is consistent with our statement in the recent letter to Uganda’s president Yoweri Museveni:
From a scientific perspective, the causes of homosexuality are only partially understood. While it is unlikely that there is one simple biological or genetic cause for homosexuality in all people, there are neural, cognitive and personality differences between homosexuals and heterosexuals which appear to have at least some basis in biology.
Truth Wins Out has an interview with Alan Sanders about the study and related issues in interpreting the role of genetics in homosexuality.