Montgomery County Public Schools have barred parents from sitting in on classes in which a new sex-education curriculum will be taught, despite an official schools policy that encourages parents to visit their children's classrooms. The policy states that parents are welcome to visit their child's classroom with permission from school administrators. The policy says, "Classroom visits and conferences by parents and other persons in the school community are encouraged." Not this time. Brian Edwards, a county schools spokesman, said the parents' presence at the sex-ed classes would have a "chilling effect on the educational process." "If you're in a classroom...