I never thought of bovine taxonomy as analogous to shifting perceptions of marriage, Philip.
By the way, Brambila, isn't the Family Research Institute run by Gary Bauer? I suppose it can't be any less credible than that "liberal" APA. In addition, where did you get that definition of marriage? God? I think he has bigger fish to fry than to convey what marriage is to His chosen ones.
Migrendel, I don't invalidate sepecific APA studies on the premis that they are liberal. I tell you the reason why the study is invalid. For instance, the famous APA-sponsored twin study was done in a gay region of San Francisco, and was voulentary. The study was obviously inaccurately done. However, if one were to simply put up the argument "The APA says homosexuality is normal, and therefore it is", by simple counter argument will be "Seeing that the APA is a homosexual-run organization, that's not a very honest organization to judge by".
Nonetheless, the other source I provided (Kinsey Institute) is definately a secular source for the statistics.