There is a movement called Taking Children Seriously that advocates that a parent should never deploy arbitrary authority, but always reason a child into doing what they ought to do. I think they are nuts, but some people I respect respect them, and it might appeal to rationalists. They are somehow based on Popperian epistemology.

In a related vein I just made a Facebook page for the Association of Anarchist Parents, an organization that I have envisioned ever since my own kids were old enough to have wills of their own.