KNOW THE ARGUMENT -
1) Legal -- the people (States) have a right to define marriage because they are financially and legally invested in it. The government cannot require us to pay taxes, subsidies, enforce laws, honor licenses in the form of marriage benefits to such 'couples' without providing a return (if we so vote - as most states have). Married people do something 'extra' to earn public benefits. The return is the creation of the future - because WE ALL USE the children of the future. Our future doctors, policemen, cable guy, etc. Do not fall for arguments like "the infertile or elderly". Court cases have already noted that the government has no idea who is infertile, no idea who is medically correctable, no idea what the future holds and no authority to find out. Simply put -- it is ruled "unenforceable". In the case of two people of the same sex, however, we don't have to play stupid that they produce nothing under any circumstances to earn those benefits we subsidize. The elderly, in most cases, have ALREADY raised their children, done that work and expended their fortunes doing it - they aren't 89 year old virgins. The law applies solid common sense to these arguments. The public must receive some benefit for their investment. This argument has been repeatedly upheld by state and federal courts.
2) Health - the FDA, US Medical Board and medical boards around the world have banned those engaging in homosexuality from donating sperm, blood and organs -- because it was KILLING people. We shouldn't have to go into graphic detail to explain how misusing the body results in higher rates of cancer, hepatitis, bacterial infections, reactive arthritis, AIDS and a hundred other conditions you've never heard of except posted on this page. WHY would the public be interested in encouraging more of it and teaching or exposing it to children ? Monogamy and condoms do not prevent cancer and many others. Small, independent doctors groups have been campaigning against encouraging these pseudo-marriages (we've posted them - the ones not beholden to large left wing donations).
3) Religious - besides your religious doctrine (since every religion opposes the behavior, most likely established millenia ago due to the disease issues - even the EGYPTIANs commented on it), there is the fact that while certain groups stomp around talking about their rights - what they really mean is what they WISH was their rights because there is only ONE specified constitutionally protected BEHAVIOR, and that is the RIGHT TO RELIGIOUS FREEDOM. "Because God says so" is not a public policy argument - it is an argument of personal religious conviction and that is fine. But God gave us brains to make effective public policy arguments too. A lot of people rightfully understand and respect your personal convictions but are waiting to hear why those who don't share your faith should be subject to your personal convictions. The "religious public policy" answer to that is that religion is constitutionally protected and sexual preference is NOT. Imposing the behavior on you, your children, your place of work, your business or in any unreasonable way in your life is a violation of a real constitutional right that we need to fight to retain and protect. It isn't that we're imposing religion on others - it's that the Constitution protects us from them imposing their ways on us. Passing marriage laws that violate our ways by force of law violates the 1st Amendment.