New Genetic Regions Associated With Male Sexual Orientation Found
Jan. 28, 2005 - "The genes a man gets from his mother and father may play an important role in determining whether he is gay or not, according to a new study likely to reignite the "gay gene" debate.
Researchers say it's the first time the entire human genetic makeup has been scanned in search of possible genetic determinants of male sexual orientation. The results suggest that several genetic regions may influence homosexuality.
"It builds on previous studies that have consistently found evidence of genetic influence on sexual orientation, but our study is the first to look at exactly where those genes are located," says researcher Brian Mustanski, PhD, a psychologist at the University of Illinois at Chicago.
Those previous studies looked only at the genes located on the X chromosome. Genes on this chromosome are only passed to a son from his mother. But this study examined genetic information on all chromosomes, including genes from the father.
The findings show that identical stretches of DNA on three chromosomes were shared by about 60% of gay brothers in the study compared to the about 50% normally expected by chance."
New Targets for Gay Gene Research
"Elliot S. Gershon, MD, professor of psychiatry and human genetics at the University of Chicago, says the study represents an important step forward in understanding how genes affect human sexual orientation.
"It is worth testing genes within a region of linkage to see if one of them has a variant that is more frequent in men who are gay than in men who are not," says Gershon, who is also currently involved in another study of gay brothers and genetic influences on sexual orientation.
"This report adds to the legitimacy of research on normal variations in human behavior," Gershon tells WebMD. "There is an argument that has been made in public press that it doesn't make sense to study conditions or traits that are behavioral. But this suggests that there is a genetic contribution to this particular trait of same sex orientation."
