Government can tell you things to or not to do that are by some definitions "immoral" - a legal argument here is moot. You talking utilitarian principles - not libertarian ones.

A civil libertarian would reject the notion that a government should restrict you from a personal activity (which parenting certainly is) - because of society's majority judgment against it. They'd easily call this tyranny of the majority - whether you agree with it or not.

However, a "classic liberal" would come at this from a natural law or humanist perspective and say there is a moral reason to do / not to do such things.

There is a distinction between civil libertarians and classic liberal civil liberties.