Are people born to be gay, or do they choose to be gay? Humanity has struggled with this question throughout history, and the issue of homosexuality in its very essence has engendered enthusiastic debate. Because many believed that choice influenced an individual’s sexual orientation, many homosexuals were fearful of coming out and openly admitting that they chose to be gay — and publicly shamed, especially by many religious denominations. However, if sexual identity or preference were inherent — that is, genetic, or predetermined or created by God — attitudes towards homosexuals would probably be very different, and most likely less hostile than those today.

[Homosexuality] is driven by the presence of genetic markers, or specific DNA sequences…

Homosexuality is a characteristic that is common in about 10 percent of the human population. According to a recent study, homosexuality is influenced by genetics. However, homosexuality is not driven by the presence of a “gay gene”, which is what epigenesists have strived so hard to discover for the past several years. Rather, it is driven by the presence of genetic markers, or specific DNA sequences, located on two different chromosomes associated with the male sexual orientation. Researcher Alan Sanders and his teammates concluded that their results from genetic analysis, finalized this year, are analogous to the conclusions of a smaller study conducted by Dean Hamer of the US National Cancer Institute in 1993, which also pointed to a similar region on the X chromosome as a potential cause for homosexuality.

Sanders, researcher at the NorthShore Research Institute in Illinois, collected blood samples from 409 pairs of gay brothers, including pairs of non-identical twins, over the course of several years. Sanders and his research team then went through each of the samples, observing the genetic markers shared by everyone in the study. All 818 subjects studied in the experiment varied in their physical traits, including height, hair color and intelligence; they each possessed unique genetic markers corresponding to their unique physical traits. The only quality they all shared was their sexual orientation: they were all gay. Therefore, Sanders and his team concluded that if the same genetic variants appeared in some of the subjects, then there was enough reason to believe that those genes had something at least remotely to do with sexual orientation.

Based on their observations, the Xq28 region of the X chromosome and the 8q12 region of chromosome 8 were the two most frequently shared genetic markers; these two regions possessed the common genetic marker, or gene product, that was associated with the phenotypic trait of homosexuality. Scientists have speculated in the past that the genetic marker for homosexuality — on the X chromosome in particular — may have survived through human history because it happened to make women who carried the trait more fertile; traits on the X chromosome are passed down to men exclusively from their mothers. Though such a hypothesis is yet to be proven correct, the same Xq28 region of the X chromosome has been mentioned multiple times in previous studies examining the relationship between genetics and homosexuality. Michael Bailey, psychologist at Northwestern University, for example, pointed to the same genetic marker in his research presented at the American Association for the Advancement of Science in Chicago earlier this year. Though the results require a more precise explanation of the mechanism of gene expression and sexual preference, it certainly confirms that there are genes involved in the process.

However, not all men in Sanders’ study inherited the same Xq28 region, which makes the experiment data insufficient to make conclusions about the direct relationship between homosexuality and genetics. Furthermore, Sanders’ research technique, called genetic linkage, merely established vague relationships between broad regions of chromosomes that contain numerous genetic markers; his procedure was outdated, and has been largely replaced by more accurate genome-wide association studies, which identifies the specific gene being studied. Though there are more factors, including an individual’s upbringing and other environmental elements, scientists have made a step forward in determining nature’s contribution to sexual orientation.

Sources

Blue, Laura. “New Insight into the (Epi)Genetic Roots of Homosexuality.Time. Time, 13 Dec. 2012. Web.

Engelking, Carl. “Study of Gay Brothers Suggests Genetic Basis of Male Homosexuality.Dbrief. Discover Magazine, 18 Nov. 2014. Web.

Sample, Ian. “Male Sexual Orientation Influenced by Genes, Study Shows.The Guardian. The Guardian, 13 Feb. 2014. Web.

About The Author

Board Secretary

I am a freshman this year, interested in hopefully majoring in Molecular Biology with a GHP and a Neuroscience certificate. Science, research, or labwork is I think where my future lies, but writing and reading are also two of my major passions. I love eating, traveling, and most of all, falling asleep on a rainy day while watching a movie in bed. I am happy to be serving on Innovation as the secretary this year, and hope to get to know everyone on staff better! :)