BOB HIRSHON (host):
Modeling gay evolution. I’m Bob Hirshon and this is Science Update.
Genes that make women more fertile may contribute to homosexuality in men. This according to psychologist Andrea Camperio Ciani of the University of Padua in Italy. He and his colleagues tested various models of gay genetics. The only one that fit the existing data involved something called "sexually antagonistic selection," involving at least two alleles, or gene variants.
ANDREA CAMPERIO CIANI (University of Padua, Italy):
That means that these particular alleles give an advantage to one sex, at the cost of the other one.
His team had already found that female relatives of gay men, on the maternal side, have more children than average. So he says the genes may have reached an equilibrium, in which the female carriers’ high fertility offsets lower paternity rates from their gay male relatives. I’m Bob Hirshon for AAAS, the Science Society.