Our society has decided we want to encourage marriage between different-sex couples and that we want to encourage procreation. That encouragement takes the form of tax breaks.
You disagree, fine. But you need to change our society's collective mind. In our society that's accomplished through lobbying, cash donations, and (mis-)education of the public, and voting.
We're currently in the middle of such a debate about encouraging marriage between same-sex couples. This will probably happen at some point because there is no real reasons not too.
But I don't think you're going to have much success convincing people that we shouldn't encourage, or should actually discourage, stable households and the continuance of our species.