Why Gays Don't Go Extinct

http://www.livescience.com/health/080617-hereditary-homosexuality.html
By Clara Moskowitz, Staff Writer

"Homosexuality in males may be caused in part by genes that can
increase fertility in females, according to a new study.

The findings may help solve the puzzle of why, if homosexuality is
hereditary, it hasn't already disappeared from the gene pool, since
gay people are less likely to reproduce than heterosexuals.

A team of researchers found that some female relatives of gay men tend
to have more children than average. The scientists used a computer
model to explain how two genes passed on through the maternal line
could produce this effect."