On the contrary, the parent has every right to prevent their children from being sexually active. If they don't the kid should not be forced to bear a child simply so you can shirk your own parental responsibilities.
So in every case when the child would need a parent's permission to buy this stuff, they would automatically say HELL NO???
What about the parents that allow thier kids to be sexually active, but want to know what the hell the kid is taking?
Also, how do you explain the lack of a need for a perscription from a doctor? They are an outside party, surely a girl who doesnt trust thier parent can find a single doctor who would write a script for this??