Why do so many mature american shows and movies take place in highschool?
As a non-american I've recently noticed this. There are a lot of american shows and movies with very explicit content that take place in highschool.
Most of the time, the school plays little to no part in the storyline. The characters never study and almost rarely attend any class .You can change the school with college or university and nothing would change.
In fact it would probably be more appropriate for the characters to be adults in college given the sexual material instead of being teenagers in school.
Also the characters generally behave more like adults in their 20s instead of teenagers so wouldn't it make more sense to write them as college or university students instead of writing them as highschoolers?