I could argue either side for what this school decided to do. But we are raised by a family and in a society. I think it is unrealistic to assume that a child will be unaffected by the sins of a parent. All of us have been affected one way or another by our parent's sins. How could it be otherwise? This mother has been granted a God-given responsibility to raise this child. She does not have a right to squander it and expect the rest of the world to protect her child from her choices. Still, I can see both sides from the school's point of view.
Good point. Assuming the school should accept the child, who is going to enjoy the jurisdiction that will enforce such conduct? Does the government or some other "neutral" organisation has the right to impose on the school and the parent/child a resolution? I do not think that this dispute is a good enough reason to get the government involved lest it starts legislating and treading on grounds on which it has no rights.