A team of scientists have concluded that there probably isn’t a gay gene. Sexual orientation, they say, has nothing to do with genetics, and is something in the DNA that is expressed in the womb.
Okay. I’m going to try to get through this science as best I can.
In The Quarterly Review of Biology, researchers at UC Santa Barbara and Uppsala University in Sweden have concluded through their research that sexual orientation can be decided through epi-marks, which are temporary switches in a fetus’ DNA that exist while in the womb and shortly after birth.
Unlike most genetic switches, they are passed down from the opposite sex parent: Father to Daughter, Mother to Son. Most of these marks aren’t supposed to be passed from generation to generation and they are essentially tossed to the wind. This explains why homosexuality seems to run in families, but without any obvious genetic markers.
Epigenetic markers are “an added layer of information that clings to our DNA,” and regulate the expression of genes according to an external trigger.
i09 puts it best: “Genes are basically the instruction book, while epi-marks direct how those instructions get carried out. For example, they can determine when, where, and how much of a gene gets expressed.”
What’s interesting is that these epi-marks are produced from scratch. They can be passed down from generation to generation, but the process starts from zero every time. They’re actually made to protect the fetus from too much natural variation. When testosterone gets too high, the epi-marks kick in to prevent the baby girl from getting too masculinized, and the inverse is true for boys.
So as a side-effect of that, one of the triggers affecting sexual orientation may kick in as well.
At least, that’s how I’m understanding this. Here’s the study via JSTOR.