Homosexuality is one of most the disputed and debated topics in today’s world, but where does biology fit in? Is there any biological reason for being born gay? If it is genetic, how could being gay possibly advance the human species or get passed on if there is no reproduction that can happen? I’ll address these questions and more by taking a look at Xq28, or as it’s known by some “the gay gene.”
Xq28 isn’t actually a gene at all; it’s a region on the X chromosome (which all males get from their mothers) and actually has portions that code for many different things. Think of it like a chapter of an instruction manual where each sentence might tell you how to do something different. Xq28 is a chapter, and homosexuality may be a sentence in that chapter.
Some scientists have noticed a relationship between Xq28 and homosexuality in males, but clear comprehension of that relationship is far from understood.
The Online Mendelian Inheritance in Man cites Xq28 as coding for many different things including the HSM1 or GAY1 gene which is described as “?Homosexuality, male.” In the details, various studies on the region are explored in relation to homosexuality in males.
A great way to find out about this is to compare identical twins. Two identical twins are going to have the same genetic make-up, but we know that they exhibit different characteristics. One study found that if one twin male was gay, there was a 52 percent chance that the other would be. Other results from studies do not support an X-linked gene underlying male homosexuality. There’s a lot still up in the air about this and part of it is because genetics is a complex thing.
Genetics is not just going to say that if a gene is present that people show certain traits and if it isn’t they won’t. There are often a variety of genetic and environmental factors that go into things. Sometimes a person’s environment can even command (to an extent) what is expressed in a person’s DNA in an awesome field called epigenetics which warrants its own discussion in a future column.
Homosexuality is not a topic that can be fully explained by simple genetics or by science at this point. That doesn’t mean it won’t ever be fully understood or that there aren’t reasons for the trait to continue on within a population. It can be found in many different species and some scientists suggest that homosexuality in a population may benefit the group as a whole by allowing those individuals to help care for their relatives’ children or that the female relatives of homosexual males are actually more fertile from Xq28 being present. The point is, genetics is certainly not a tell-all for determining an individual’s sexuality or explaining it, but it might be able to share some insight and be further explored.