I certainly agree that there should be model policies in the interest of protecting children from untoward content of a sexual nature at public school and to honor the rights of parents to decide whether or not their children should be exposed to such sexual content. Some content is viewed as totally inappropriate regardless of the children's age because they are against societal norms shaped by a Judeo/Christian moral framework. Even with that in consideration, age appropriateness needs to be evaluated by parents as to the timing of first exposure to sexual content.
Further, as to who decides, this falls squarely within the range of fundamental rights that parents have. This responsibility has been given to them by God, not the state. Parents have consciences that govern matters of appropriateness in determining what is best for their children.
Please ensure through this document that there are specific actions that every school should take, so as to confirm that sexually explicit materials are clearly and correctly identified and seen by parents first. If there is a failure to do so, schools may find ways to circumvent what they consider to be mere guidance.