In new research and an analysis of more than two dozen earlier studies, Schumm found that 27 percent of lesbian parents' children identified themselves as homosexual, and 19 percent of the children of gay men; by contrast, 5 to 10 percent of the children of heterosexual parents self-identify as homosexual.
Furthermore, Schumm observed gay parents' children increasingly identifying as homosexual as they emerged from adolescence. His analysis of families with older children showed that one-third of gay fathers' families, and 58 percent of families of lesbian mothers, included at least one gay or lesbian child.
“Most scholars actually agree with the concept that gay people ought to be more likely to have gay children,” he told CNA in an Oct. 19 interview. “Even people on the liberal side of things actually pretty much agree with the idea that there are going to be social influences.”
He noted that prominent gay activist Jim Burroway has criticized proponents of the “parental influence” theory but has also said that such findings would not be surprising. In a column published on a gay and lesbian website in 2006, Burroway noted that virtually every theory about the origin of homosexuality would likely predict a higher incidence in children of gay parents.
Schumm wanted to test that prediction, and to improve on previous research he said was too limited and not sufficiently rigorous. He analyzed data obtained from 26 studies of gay parents and their children. He noted that many of the studies' authors had dismissed the idea of a parental influence on children’s homosexuality.
Those researchers, Schumm believes, chose to ignore or downplay the significance of their own findings. Even when attempting to disprove his hypothesis -- for instance, by classifying the significant number of respondents who showed no clearly defined sexual preference as “heterosexual” in the analysis, or assuming that up to a third of those identified as homosexuals could have been erroneously categorized-- Schumm consistently confirmed the hypothesis among 218 families.