Mothers' genetic skew linked to gay sons

10:26 09 November 04

Exclusive from New Scientist Print Edition.


There has been much debate over “gay genes”. Now an intriguing study raises another possibility: in some cases, variations in the genetic program we inherit from our parents, rather than in the genes themselves, might determine sexual preference.

Our genome is “programmed” by the addition of chemical markers called methyl groups to the DNA, which shut down genes. One of the most dramatic examples of methylation is the shutdown of one of the two X chromosomes (one from each parent) in every woman’s cells, a process called X-inactivation.

Normally, this process is random; either of the X chromosomes can be inactivated.

But when Sven Bocklandt of the University of California, Los Angeles, compared blood and saliva samples from 97 mothers of gay men with samples from 103 mothers without gay children he found this process was extremely skewed in the mothers with gay sons, with one X chromosome being far more likely to be inactivated than the other.

link to New Scientist article