Please explain your "Pandora's Box" theory. Again, please look up slippery slope. Yup, described as "a fallacy".

I'll go further on the bestiality/polygamy theory. The current law allows any two PEOPLE, a man and a woman to marry. Since the law applies to everyone equally, any TWO people should be allowed to marry. It's not that much of a stretch considering the fact that the 14th Amendment has already been interpreted to forbid discrimination based on gender, color or creed.