All this research, of course, is politically charged. Geneticists I know say it's very difficult to study whether homosexuality has a genetic base. For one thing, it's hard to get people to participate in such studies in the first place. Then, it's not clear whether you're getting accurate information. Finally, scientists disagree about how to identify a person as gay or lesbian.
Researchers say the picture is getting more and more complicated.
If there is a genetic root to homosexuality, they say, it definitely won't be the action of just one gene, but the interaction of many. Even Dean Hamer, a strong proponent of a genetic cause, points to the studies of twin brothers to show that half or more of the variability in sexual orientation is not inherited. And some critics of his work and other researchers looking for a biological root to sexual orientation question the essential assumption that men have to be either gay or straight. Sexuality is a continuum of behavior, they say, not a species. Inc. All rights reserved.