Sex is one of the most personal, emotional things two people can share together. That's why parents balk and have some stranger tell their kids about it instead. I agree school should teach basic health, hygiene, and sex education, but parents should be leading the discussions at home first. Unfortunately, they don't. At Dallas Public Schools, kids start dropping out as early as fifth grade to have babies.
Teachers also have to teach discipline.
It used to be when kids were younger, they learned discipline at home and good behavior carried over to school. Now they're lucky if they learn any discipline at all. Teachers aren't teachers any more. Your plan would work great if we all lived in a white, suburban, middle-class world. But we don't.