Homosexuality is the gateway behavior that leads to sick and abnormal sexual perversions..........
Homosexuality doesn't lead to any kind of behavior other than homosexuality. But, once homosexuality is accepted as normal behavior it absolutely opens the door for any other kind of abnormal behavior to demand its own acceptance.
Not so sure about that, because at some point a majority of homosexuals will say "uh whoa, too far thier buddy." It happened previously with NAMBLA, and I doubt a majority will get on the incest/beastiality bandwagon.
Now plural marriage, on the other hand, is something we may see next.