The cause of homosexuality

I saw a post on a Facebook page today that got me doing a little research. This isn’t my favourite subject. I much prefer physics and technology to biology and psychology. Obviously people who have devoted a lot of time and attention to this subject have a lot more information upon which to base their opinions. But many of them are of differing opinions. Surely those of us who have only casually considered the issue are entitled to form a tentative opinion without being subjected to ad hominem epithets? Ha, wishful thinking. But I am not dissuaded.

The post was about a billboard someone had erected saying that research studies on identical twins showed that people are not “born gay”. It seemed to me that such studies ought to shed some objectivity on the subject so I found an article entitled, Identical twin studies prove homosexuality is not genetic. The source for the story seemed highly qualified and the claims in the piece are well-annotated, referring to various studies.

The key part of the article was:

Identical twins have the same genes or DNA. They are nurtured in equal prenatal conditions. If homosexuality is caused by genetics or prenatal conditions and one twin is gay, the co-twin should also be gay.

“Because they have identical DNA, it ought to be 100%,” Dr. Whitehead notes. But the studies reveal something else. “If an identical twin has same-sex attraction the chances the co-twin has it are only about 11% for men and 14% for women.”

Because identical twins are always genetically identical, homosexuality cannot be genetically dictated. “No-one is born gay,” he notes. “The predominant things that create homosexuality in one identical twin and not in the other have to be post-birth factors.”

That was pretty persuasive but I kept looking because I wanted to see if I could find someone offering a different interpretation. I found an article written by a geneticist in response to a question asking whether someone was “born gay.” The author stated, without referencing any source material, that twin studies show that if one twin is gay there was a 50% likelihood that the other would be. This is far higher than the research referred to in the first article showed but still less than the 100% one would expect if it were purely in the genes.

I wonder if the difference stems from misinterpreting the stats. That would strike me as an inexcusable blunder for a scientist, whether due to negligence or bias. There is no consensus on what percentage of the population are homosexual, I think, largely because there is little agreement on what it means to be homosexual. Is it to have had any same-sex attraction anytime in your life (one extreme) or to be actively engaged in sex with same gendered individuals (the other extreme).

I think this quote from the second article makes the most sense:

Right now the best guess is that people inherit a set of genes that makes them more or less likely to respond to something in the environment in a way that causes their brains to be wired so that they are attracted to people of the same sex.

The quote references a genetic factors, environmental factors, and, importantly, choice – by speaking of it as “more or less likely” and not as being absolutely predetermined by either genetic or environmental factors.

So, are some “born” homosexual? That’s too broad a question. Are some born with a predilection for same-sex attraction? I think that’s true though I haven’t seen any persuasive explanation of how natural selection can account for this. But this is only a predilection, a bias, a tendency, an inclination. It puts the matter in issue as a subject requiring a decision but it does not impose the decision. To someone without the predilection, the issue never arises. But to someone with this genetic predilection, it does and requires a decision.

If there is no genetic component, or there is but it is absent in a particular individual, there still may be a significant environmental stimuli. How strong each, or both of these are determines the degree to which same-sex attraction is a matter of choice. I doubt that it ever feels like “a” choice because it probably results from a series of voluntary responses over time, none of which, taken alone, would feel like this was the issue at hand.

I think that one or more genetic and/or environmental factors needs to be present to place the issue on the table. Absent this, same-sex attraction is not something that occurs to a person. But when such factors are present, in the course of his/her life, a person continues to have a multitude of experiences, each of which can strengthen or weaken the predilection to same-sex attraction depending on how the person chooses to respond within the experience.

I perceive the need to defend that statement, though I think it is clearly true. Because clearly, it is not simply genetics that determines the existence and strength of same-sex attraction. And once you recognize that there are environmental factors you thereby bring choice into the equation. Unless you are a helpless paraplegic on a deserted island, the consequences of your choices and the choices of others around you are among the environmental factors that influence you.

So a person is born with a genetic predilection, which is reinforced by early environmental factors, which is further reinforced by how the person chooses to respond to situations. At some point a person becomes aware that s/he is consistently experiencing same-sex attraction and may, and quite accurately, feel that they really always have. But in fact, it is something that has been building up through the course of life, as a combination of genetics, environment, and personal choice. It appears clear that with many the strength of the attraction reaches the point where if feels like a compulsion, like a part of who they are. But it is more accurate to say that it is a part of who they have become.

Accordingly, I conclude, tentatively, that anything that normalizes and encourages same-sex attraction, also fosters it. There is no neutrality. By normalizing it for children, still developing their sexuality, you are providing an environmental factor which reinforces the predilection and therefore, makes it more likely to come to feel like a compulsion – like “who they are.”

And what’s wrong with that? Well, that’s a question of whether one sees value in the traditional family structure. There is a clear value to it in terms of preserving our species. But sociological surveys also support the conclusion that children are better served by being raised in such a structure. Also that heterosexual relationships last longer and are happier than same-gender relationships.