Want to know a quick way to take the air out of the argument that being gay is "unnatural?" Break out the Kin Selection Hypothesis!
People sometimes claim that being gay is unnatural because since two men and two women cannot reproduce together, same sex relationships serve no evolutionary purpose. An "evolutionary purpose" is basically something that gives someone's species a better chance at surviving. As the About Guide to Evolution explains,
"Evolution is a scientific theory that essentially states species change over time. There are many different ways species change, but most of them are based on the idea of Natural Selection...Sometimes called "survival of the fittest," Natural Selection was most famously explained by Charles Darwin in his book "On the Origin of Species." In the book, Darwin proposed that individuals with traits most suitable to their environments lived long enough to reproduce and passed down those desirable traits to their offspring. If an individual had less than favorable traits, they would die and not pass on those traits. Over time, only the "fittest" traits of the species survived."
Unfortunately, this theory has been used to justify discrimination against GLBT individuals by people who claim since humans cannot reproduce with the same sex, sexual relationships between them are "unnatural." (Of course, those same people often think it is just fine for opposite sex people to have sex even if they don't plan on getting pregnant. And few would advocate preventing people who were infertile and unable to have children from marrying).
Others don't go so far as to argue that gay people should be denied rights because of who they are, but often still assume that from an evolutionary perspective being that being gay must be some kind of mutation or anomaly. Indeed, some GLBT people themselves hold this view. As one bisexual teen writes of being gay, lesbian or bisexual, "I think it is caused by a mutated organ, cell, or hormone."
But what if there was actually an evolutionary benefit to being gay? According to Paul Vasey and Doug VanderLaan, two Canadian evolutionary psychologists, there is indeed one!
Called the kin selection hypothesis, this view holds that because they are less likely to have their own children, gay men and lesbians actually help ensure the survival of children to whom they are related. The idea is that gay men are biologically predisposed to help raise the offspring of their siblings and other relatives with whom they share genes (the segments of DNA that are passed from a biological parent to his or her children and which determine some characteristics of those children).
As the Association for Psychological Science explains,
"What that means is that homosexuality may convey an indirect benefit by enhancing the survival prospects of close relatives. Specifically, the theory holds that homosexual men might enhance their own genetic prospects by being “helpers in the nest.” By acting altruistically toward nieces and nephews, homosexual men would perpetuate the family genes, including some of their own."
In other words, the more grown-ups a kid has helping raise them, the more likely that kid is to survive and thrive. And those who survive and thrive are more likely to reproduce and pass on family genes to future generations.
Now if you ask me, no one should need to justify their sexual orientation's role in the cosmos in order to avoid discrimination. But it is also pretty cool food for thought and can be a great way to take the air out of hostile arguments against being gay.