I can merely argue that I see no reason why bad things should happen, and there is no evidence to suggest that they will. But I can also argue that you have the issue entirely backward. This is not, after all, a minor right that a group of citizens are demanding, like the right to shop on Sundays, or watch network television on a cable channel. It is a right that you have never, once in your life, ever considered could be taken away from you. It is a right that you have taken for granted from the very beginning of your social being, a right that is embedded in every heterosexual's consciousness as something that is utterly inalienable from their humanity, their future, and their citizenship.
Marriage is one of the 'basic civil rights of man,' fundamental to our very existence and survival.
We are already guaranteed it by the Constitution of the United States. It is you who seek to deny a group of people, for no good reason, a right that is theirs from birth. If homosexuals were denied the right to vote, it would not be up to me to argue that no possible harm could come from our being admitted into the political system, and come begging at the door for consideration of such a revolutionary change. It would be up to you to justify this obvious and flagrant denial of fundamental equality. You suggest that this is merely an attempt to make me and my friends happy.