Homosexuality v. Evolution
This thought occurred to me yesterday, and I’m now bewildered that I hadn’t read of it before. Maybe I wasn’t paying attention.
A chief tenet among liberals (or most people, actually) is that homosexuality is genetic. It’s part of a person, and not a lifestyle choice (as some conservatives would argue). From my limited experience with friends that are gay, I would tend to agree.
However, almost all of these same people would certainly argue in favor of evolution and natural selection as well. But does genetic homosexuality jive with natural selection?
If we’re to believe that we are who we are due exclusively to evolution, wouldn’t genetic homosexuality have been “selected” out of the gene pool a LONG time ago? In fact, homosexuality has got to be the WORST trait for a species that hopes to survive and thrive. In my opinion, 100% raging heterosexuality would be way more valuable to a species than, say, the development of legs or wings or whatever!
Again, I’m not saying that homosexuality isn’t genetic. But how does an intelligent liberal justify believing in both genetic homosexuality AND evolution? Isn’t there some cognitive dissonance here?
(Side note: There is dissonance for Christians here as well, but nothing we’re not intimately familiar with and nothing that hasn’t been tackled by countless saints, theologians and everyday bible studies: “How can God punish us for our sins if he created us with our sins?”)
There are lots of genetically inherited diseases that kill children before puberty, so any theory of natural selection has to account for those too. One possibility is that homosexuality is a maladaptive mutation that hasn’t had a chance to work itself out of the gene pool. Another possibility is that homosexuality is a recessive trait that is somehow adaptive in heterozygotic form and maladaptive in homozygotic form. Sickle cell anemia and cystic fibrosis are examples of such traits (protection against malaria and bubonic plague, respectively).
In any case, we know that homosexuality can’t be 100% genetically determined because having a gay identical twin doesn’t guarantee that the other twin is also gay. Wikipedia cites studies that estimate the heritability of homosexuality to be around 30%.
I think the whole “does homosexuality have a biological basis” debate is a red herring. Heterosexual promiscuity and psychopathy also have biological bases, but that doesn’t stop us from saying that those are morally wrong. And there are all sorts of genetic conditions that we try to treat and eliminate. I’m sure that liberals would not take kindly the assertion that homosexuality is a disease to be treated, but establishing its origin in biology can just as easily lead to that interpretation.
Actually, accepting a biological basis for homosexuality (whether 100% or 30%) is not necessarily a sine qua non of political liberalism. Just a few weeks ago, Al Mohler came out saying that he thinks the scientific literature points “in the direction” of concluding in favor of a biological basis.
Today’s NYT with an article on exactly this subject.
http://www.nytimes.com/2007/04/10/health/10gene.html
Also repeats Larry Summers’s provocative hypothesis about brain differences between the genders.
Fascinating article.
Side observation: A little startling to find scientific confirmation of the so-called “honeymoon period” of a relationship.
“Romantic love, which in its intense early stage ‘can last 12-18 months,’ is a universal human phenomenon…and is likely to be a built-in feature of the brain.”
More disconcerting is that I’m currently in my 19th month of marriage. Science be damned!