Research by a team of Italian researchers suggests a genetic link between homosexuality and fertility.
A study of 98 homosexual men, 100 heterosexual men, and their relatives (4600 people) indicates that female maternal relatives of homosexual men tend to have more children than female maternal relatives of heterosexual men. This was not true of female paternal relatives.
The lead researcher, Professor Andrea Camperio-Ciani, of Padua University, attributed to his 15-year-old daughter the idea that there is a genetic factor linked to both homosexuality and high birth rates. This, she suggested, could help explain the anti-intuitive persistence of genes, such as the so-called "gay gene" (Xq28) that apparently contribute negatively to the production of offspring.
Prof. Camperio-Ciani stressed that his study explained only 20 per cent of the variance in sexual orientation of males; otherwise homosexuality would be much more common. "The remaining 80 per cent has yet to be understood," he writes. "It could—and in fact partly is—due to cultural and individual experience, or even by undiscovered biological factors."
Most intriguing is the conclusion that the incidence of homosexuality can be expected to be greater in societies with declining birth rates, because the influence of this genetic factor is more significant.