Parents have always had plenty of say where I am from. But parents ALWAYS have a say in how they raise (or don't raise) their children no matter what. My parents knew that. If things came up in the school (in the few times it did), we/they were able to deal with it because they raised us to be able to do so. None of us eight children never had probems with drugs or alcohol (actually never touched them) or such things. My parents were strict in the fact that we never had video game systems or cable TV (didn't need them) and that they expected us to do our homework--no friends over on school nights. We had plenty of religious time too so that wasn't a factor and they did expect us to learn something at school and to respect teachers. We've all had bumps along the way, but have all turned out fine. That was the most important thing to my mom--is that we all turn out to be good kids. I respect her enough to honor that and try to keep being a "good kid." No, we don't know Latin and we didn't go to Harvard, but we have turned out just fine.
~sigh~ Would that all children had good parents like we (you and me) did.
It isn't a constitutional issue.