Your slippery-slope argument doesn't cut it. Homosexual relations do not affect anyone outside of the relationship. Pedophila does. There is NO groundswell movement to legalize sex with children, and you know as well as I do that it will never happen.
What is is it about "informed consent" that you don't understand? Two adult men or two women can give consent, but we have determined that children cannot give legal consent. And I have yet to meet an animal that could say, "My place or yours?"