Either your school is mistaken or your child is mistaken. While children are not property of their parents and have certain rights parents may not transgress--e.g. parents may not deny children food, water, education, etc.--fundamentally, except for those "big ticket" items, children are subject to their parent's control. In fact, parents can face liability for NOT controlling their children adequately, if the children then injure themselves or other people.  In some circumstances, an old-enough minor (e.g. 16 - 18) can be legally "emancipated" if the parents do not act in the child's interests, but that is a rare case involving exceptional situations. You might wish to contact the school and find out what exactly is being taught and seek their help in correcting this misapprehension.