Homosexuality can be predicted by a gene scan with 70 percent accuracy, study reveals

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Oct 09, 2015 06:00 AM EDT

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US researchers have come up with a gene scan that can predict a man's sexual orientation and preference with 70 percent accuracy.

The predictive model was born out of the study by the researchers on molecular markers in the DNA. The study has yet to be published but it was presented at a meeting of the American Society of Human Genetics in Baltimore, according to Reuters.

For the study, researchers looked at 47 pairs of twin brothers. In the 37 pairs, one brother was homosexual and the other was straight. The remaining 10 had brothers who were both homosexual. Tuck Ngun, a molecular biologist and lead researcher from the University of California, Los Angeles (UCLA), looked at the genes of the participants. He found "epigenetic marks" in the genes. These molecular marks are associated with male homosexuality and can predict sexual orientation nearly 70 percent, according to the Los Angeles Times.

The researchers came up with a formula via a computer algorithm to check out the patterns in the gene to suggest homosexuality in males.

"To our knowledge, this is the first example of a predictive model for sexual orientation based on molecular markers," said Ngun in a statement, via Reuters.

The results come from preliminary research and experts caution the study's limitation makes epigenetic markers unreliable for definitive conclusions.

A genetics professor from University of Utah spoke up and questioned if the prediction can be applied to other samples other than twins. Another professor from Emory University who attended the meeting stated that their participants are too few to stake any claim.

According to Dr. Margaret McCarthy from University of Maryland School of Medicine, the study shows that epigenetic changes could occur in a mother's womb.

"Developing male fetuses produce very high quantities of testosterone during the second trimester and this directs psychosexual development along masculine lines, a component of which is preference for females as sexual partners," McCarthy said, via NBC News.

"This study provides a major step forward in our understanding of how the brain can be affected by factors outside of the genome. It is also possible that the experience of being a homosexual or a heterosexual has itself impacted the epigenetic profile. But regardless of when, or even how, these epigenetic changes occur, their findings demonstrate a biological basis to partner preference."

However, according to Christopher Gregg, a geneticist from the University of Utah, the epigenetic marks may be linked to homosexuality but it might be not what causes it.

"Epigenetic marks are the consequence of complex interactions between the genetics, development and environment of an individual," Dr. Gregg said, in a statement, via LA Times.

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