Being gay part of
the "X" factor?

Adding to the ongoing debate over whether being gay is a choice, new research released on Tuesday suggests the genetics of mothers with multiple gay sons are different than those of other women. The findings looked at 97 mothers of gay sons and 103 mothers without gay sons and compared how the women processed their extra X chromosome (women have two X chromosomes but require only one and routinely inactivate the other). The study found that almost a quarter of mothers with more than one gay son processed X chromosomes in the same way.

The research "confirms that there is a strong genetic basis for sexual orientation and that for some gay men, genes on the X chromosome are involved," study coauthor Sven Bocklandt, a postdoctoral researcher at the University of California, Los Angeles, told the HealthDay Reporter. "When we looked at women who have gay kids, in those with more than one gay son, we saw a quarter of them inactivate the same X in virtually every cell we checked. That's extremely unusual."

Most women inactivate their extra X chromosomes at random, and the phenomenon of being more likely to inactivate one specific X chromosome--like the mothers of multiple gay sons did--is typically seen only in families with genetic irregularities.

Other scientists were more skeptical of what the study proved. Dr. Ionel Sandovici, a genetics researcher at the Babraham Institute in Cambridge, England, described the study as small and pointed out that most of the mothers of multiple gay sons didn't share the unusual X-chromosome trait. The origins of sexual orientation remain "rather a complicated biological puzzle," Sandovici said. (Advocate.com)