The two genes MAO-A and 5-HTT have drastically different effects on male and female behavior, according to Swedish researchers at Uppsala University. Major Swedish daily "Svenska Dagbladet" reports:

Gene variants that in a given environment lead to alcoholism, depression or antisocial behavior in boys have the opposite impact on girls. And vice versa.

In the study, 5000 swedish youths completed a behavioral survey. From this sample, 200 youths were selected for further interviews and blood tests. Teachers and parents were also interviewed. According to SvD:

The results were clear. A short version of the gene MAO-A for boys and a long variant for women in combination with a problematic social environment meant for example an increased risk for alcohol-related problem behavior. When boys had the long variant and girls the short one, the results were reversed.

"The impact is very small when only looking at environment or genes in isolation. But there is a tremendous increase in the effect when they are combined", says Lars Oreland. "

Results have been published in several journals, among them American journal of medical genetics and Journal of biological psychiatry.

Media-related side note: This news is splashed all over the news in Sweden, with zero "anti-genetics" jibes in sight. Which is interesting.

Previously on GNXP about MAO-A.