By in and out, we are talking about what the legal definition of marriage should be? (Not what informal unions will be tolerated by law).
What's wrong with leaving it defined as one man and one woman? This is the traditional and sensible definition, based on the fact that their sexual union may result in children that need protection. To cause the legal definition to diverge from a very well established tradition and the states' own centuries-long definition should require an enormously sound reason. What is it?
By the way, you do know that Israel lets out of the closet gays into its military didn't you? I just thought I would share that little faclet with you. Notice, I didn't mention Europe, since someone would then assert that that was what "caused" their militaries to become so enervated. Why bother going there, when one can just adduce hyper macho Israel instead.