I call them hormones with feet :)
Parents are the most influential imo but these aren’t children. They’re teens (and not so long they were considered adults) and they’re going to do whatever they do when it comes to sex. I don’t think teens were having less sex back in the 50s or so or whenever, they just weren’t letting anyone know.
Well, they were getting married younger (marriage didn't seem as distant as it does to today's teens), there were a lot less dual-income families without moms at home, and girls dressed more conservatively. That had to have had some effect on teen sex.