Chief Science Correspondent
On June 5 I wrote an article in which I discussed geneticist Jenny Graves’ research on a “male-loving” gene that could influence homosexual attraction in men.
The existence (or non-existence) of a "gay gene" is important to many people because a genetic predisposition to sexuality could provide support for the argument that homosexuality is not unnatural and also not the result of a conscious choice.
However, even as various studies yield results that suggest the existence of several candidate genes that could influence sexual preference, opponents continue to form arguments that often incorporate these findings. Earlier this week, Rick Perry compared a predisposition to homosexuality to an individual's inherited risk of developing alcoholism.
Another popular argument is that if sexual orientation is controlled by specific genes, homosexual individuals could be "cured" via gene therapy. Even if this concept was not morally repulsive, there are still a number of reasons the proposal is highly impractical and unrealistic.
First of all, gene therapy is ideal for treating conditions that are solely genetic. Gene therapy works by supplementing a non-functional mutant gene with a working copy, so that previously deficient proteins can be produced and make up for the deficient molecules.
For instance, if you happen to have been born with extra CAG repeats in the HTT gene, you'll develop a condition known as Huntington's Disease that affects 30,000 people in the U.S. If you have the mutation, you get the disease. If you don't have the mutation, you won't. Simple as that. So if scientists can target specific sequences and provide a functional copy of HTT, the disease can be cured.
However, very few diseases or human traits are affected by one gene sequence, and they don't always necessarily result from a single nonfunctional protein. Hemophilia and cri du chat are two disorders whose origins have been similarly linked to specific genes. They are often used as case examples in biology classes because they are easier to describe.
Remember in 7th grade when you wrote out Punnett squares to track the dominant and recessive alleles that affect brown/blue eye color? In real life, it's actually much more complicated. Most human traits are a result of several interacting genes, as well as certain environmental factors.
Certain genes have been linked to skin cancer, but gene therapy isn't going to help the girl who goes to the tanning salon every month. Gene therapy won't stop the man who eats Five Guys every Friday after work from having a heart attack.
So yes, Rick Perry; in a way you're right. You can be more than your genes. And you can control your own behavior and choices in life. However, when it comes to certain factors that influence inherent personality, your analogy fails.
There is mounting evidence that sexual preference could be the result of genetic predisposition. And this makes sense, as much of our personalities tend to be the result of genetic factors. DNA is the basic blueprint for an individuals' life, so it makes sense that sexual orientation is somehow linked to the code. It's why twins who share identical DNA sequences tend to often share similar personalities (twin studies have long shown a support for the genetic influence of sexuality.)
However, it is highly unlikely that scientists will ever link a single mutation in one single gene to an individuals' sexual orientation across the entire human race. We've been able to track certain genetic disorders to specific genes because they are concrete. Without a specific "gay" sequence, the effectiveness of gay gene therapy is simply implausible. There's almost certainly no way we could "diagnose" a person's sexuality and describe the specific sequence that has caused it. And even if we could, it's not likely that this gene renders the target protein "non-functional." The gene might regulate the expression of several other genes, or it may produce a protein that interacts with sexual hormones.
As far as we know, a homosexual man is not physiologically "deficient." As far as we know, his sexual preferences are likely a reflection of his physical makeup, which is controlled by a combination of factors that stem from certain genetic sequences as well as environmental factors. While it is possible that gene therapy or silencing could slightly impact sexual preference, it would most likely be highly ineffective as a widespread "treatment" option.
Gene therapy is an amazing, fast-growing field that could potentially improve the condition of human life in the future by eliminating or mitigating the effects of certain diseases that cause specific physiological deficiencies that affect a person's ability to live fully.
However, being gay is not a physiological deficiency.
The fact that anyone would consider spending the time or financial resources to alter the factors impacting person's sexual orientation is insulting to the patients who would actually benefit medically from the technology.