Although I try to avoid controversial topics, like gay marriage, I have to share with you my conclusion that I could only ever answer that particular question with another question. For some time now, when asked my opinion on this subject, my best answer was that if a man can 'marry' a man, why can't he marry a goldfish? You could advance, for marrying a goldfish, every single reason that is advanced for making meaningful the 'marriage' of two men, or women. I would defy the advocates of gay marriage to advance a single valid reason against man-goldfish love. That always seemed to be my best shot at a counter-argument to gay marriage.
As usual, truth eventually trumps mere hypothesis.