Not very much at all. It really comes down to how much the parents are willing to let them--as I know from personal experience. It may interest you to know that I do actually oppose parents forcing their religion (especially heretical religions) onto their children and if it were a practical possibility to prevent them from doing it, then I would support that. But seeing that I cannot think of a practical way to prevent parents from religiously abusing their child, I am conceding political defeat to that, which is why instead I am advocating that the government stop parents from doing anything that physically harms and/or puts their children at a physical risk--even if it is motivated by their religion.
Why not just abolish the family unit so we can all live on giant polyamorous state compounds? That way, all children could be raised in the exact same environment.
And that 'sir' is the pot calling the kettle black. In your previous post, you can dismiss my altruistic views about the collective population overruling individual rights as 'utilitarianist BS' then why can't I dismiss your individualism as 'Randianist BS'? Likewise, why are we even debating labels and names of philosophical systems of thought? Debate the philosophical systems in themselves. You say that you are an individualist, then explain and defend your individualism--whether it is Randian or not.
That is the definition of utilitarianism is it not? The greater good triumphs that of the individual. Seems accurate to me. My views, however, are not entirely relevant to the discussion, but for the sake of dialogue, I am a libertarian with anarcho-capitalist leanings. Rand, as I am sure you know, did not think very highly of libertarians.
No, your views are not altruistic - they are despotic.
Try this guy along with Adolf Hitler and Mussolini.

I have never in my life heard a single speech or recording, read a single writing, excerpt, quotation, citation, or any thing to slightly suggest that either Hitler or Mussolini were supporters of individualism. Do you understand that nationalism is collectivism? Those are perhaps some of the best examples of people who were opposed individualism.
Il Duce : "
All within the state, nothing outside the state, nothing against the state." (Speech to Chamber of Deputies - 9 December 1928)
Der Führer : "
The unity of a nation's spirit and will are worth far more than the freedom of the spirit and will of an individual; and that the higher interests involved in the life of the whole must here set the limits and lay down the duties of the interests of the individual."
I actually don't give a hell about what a document written 400 years ago specifically addressing problems and circumstances that people were facing 400 years ago by fallible men 400 years ago has to say. I've said it before and I will say it again that the Constitution is merely a list of guidelines in my eyes opposed to absolute authority. Going further though, yeah, religious freedom is a good thing, but only to an extent. You Christians in America are spoiled whiny brats too used to the whole country favoring you and favoring your ideological views. Religious freedom ends when it physically harms and/or impedes upon the lives and rights of other people--including your children. This is why we don't allow those crazy Jehova Witness/Christian Science types to reject blood transfusions to their children and why hopefully we will outlaw Jews and Muslims from circumcising their children.
Not to nitpick, but the Constitution was not written even close to 400 years ago. And yes, I am not the biggest fan of it (the Articles of Confederation were much better), but its the reality of the society we live in. If you want to abolish religious freedoms, then you need to abolish the Constitution (or at least the first amendment). Until then, you can keep the tyranny. I will stick with liberty.