Although I admittedly don't yet completely understand the question's full implications.

Our everyday language is (or was at least at one point) full of expressing the idea that marriage results in children. Surely you've heard at some point in your life, "Get married and start a family." Does that not imply the expectation that children will result from marriage? I think it indisputable that most opposite-sex marriages do, in fact, result in the births of children. I recall the scuttlebutt about the hospital where my wife and I worked being that we "would never have children" because my wife wasn't pregnant in the first two years after we got married - like everyone else who was our age who'd gotten married.

I'm finished with this topic here because everyone apparently rejects my premise that State issued marriage licenses only make sense in the context of an expectation of a new generation arising from those relationships and that expectation is the basis for all codified preferential treatment under law those relationships receive. I think rejecting that premise is being dishonest of (at least) the history of marriage in the United States. But, if you can't agree on the premises, you can never agree on the arguments. And that's where we are. And I'm weary. ;0)