What if the child is a severe type 1 diabetic and needs insulin shots to survive? It is both a medical case which some claim to be of concern to the parents only and a case of real neglect equal to starvation and exposure. Whose rights take priority in that case? What if the parents are of a Christian sect that believes only in faith healing and thus insulin shots are against their religion? What if they aren't Christians but have just as much faith that all healing comes from Mother Earth?
I wish I had answers, but in general I believe that the child's right to live outweighs the parents' right to control. Take the kids away and give the insulin shots. In cases that aren't immediately life and death I'm far less certain.
It’s just so dangerous. I get wanting to save children’s lives. But what you are essentially saying is the parent is unfit because of their religious belief, in effect diagnosing their religious conviction as a mental disorder. There are many who would not hesitate to interpret it that way and run with the precedent to start defining different beliefs as disorders.