Using epigenetic information from nine regions of the human genome, scientists can now predict the sexual orientation of males with up to 70 percent accuracy.

According to research presented at the American Society of Human Genetics (ASHG) 2015 Annual Meeting in Baltimore, this algorithm is the first example of a predictive model for sexual orientation based on molecular markers.

Researchers at the David Geffen School of Medicine of the University of California, Los Angeles examined patterns of DNA methylation — a molecular modification to DNA that affects when and how strongly a gene is expressed — across the genome in pairs of identical male twins.

Researchers used identical twins because they have exactly the same genetic sequence, environmental factors lead to differences in how their DNA is methylated. The study involved 37 pairs of twins in which one twin was homosexual and the other was heterosexual, and 10 pairs in which both twins were homosexual.

Researchers found that methylation patterns in nine small regions, scattered across the genome, could be used to predict study participants’ sexual orientation with 70 percent accuracy.

Source:

American Society of Human Genetics. “Epigenetic algorithm accurately predicts male sexual orientation.” ScienceDaily. ScienceDaily, 8 October 2015.