It should be a requirement across the board. If boys and girls are separate, like in a Catholic school or a yeshiva, they shouldn’t get together just for sex education. But if boys and girls usually have classes together, then they should have sex education together. The teacher should say, “We are going to talk about a topic, and everyone can laugh about it, but I am going to give you the correct information. I am going to show you what a condom looks like , I am going to show you what other contraceptives are like.” Be careful not to do it in an arousing way, but if you can use good humor, then use it. In the Talmud, it says that a lesson taught with humor is a lesson retained.