If so many teenagers in high school are having sex, why are barely any getting in trouble?

I dont think that anyone tells the cops. I mean, the whole school may know it but do you ever know anyone who tells the cops? Plus. People are pretty good at hiding it. And mostly people deny it. I mean, If they use a condom they cant test for sperm or anything. So I dont think that many people get introuble. Not to mention all the teenagers I know are nonvirgins