evolution-based rationale for homosexuality

fascinating new research on human sexuality and the evolutionary reasons for homosexuality. from the unfortunately-titled article, Why Gays Don't Go Extinct:

"These genes work in a sexually antagonistic way — that means that when they're represented in a female, they increase fecundity , and when they're represented in a male, they decrease fecundity. It's a trait that benefits one sex at the cost of the other."

...

Since gay people are less likely to reproduce than heterosexuals, many experts have wondered why, if homosexuality is caused by genetic factors, it wouldn't have been eliminated from the gene pool already.

But if the same genes create both homosexuality in men and increased fertility in women, then any losses in offspring that come about from the males would be made up for by the females of the family.

"Sexually antagonistic selection is an old idea by Richard Dawkins, but this has never been proven in humans," Camperio-Ciani told LiveScience. "There are a large quantity of these traits found in insects, for example, and recently in deer sexually antagonistic traits have been discovered, showing that high-ranking males produce rather unsuccessful daughters. We found that sexually antagonistic selection is operating also in our species, and we found it in a very important trait, which is homosexuality."

a few possible scenarios are also discussed:

Blanchard found that with each older brother in a family, the odds increase by about a third that a boy born later will be gay. This effect is not thought to be caused by genetics, but rather by antibodies produced by the mother's immune system during pregnancy.

...

Camperio-Ciani and his team hypothesize that the genes they modeled may cause people of both sexes to be extremely attracted to men, which would lead men with the genes to pursue relationships with other men, while causing women with the genes to have more sexual partners, and become pregnant slightly more often than an average woman.

Sphere: Related Content