I remember getting a sex ed book sent home in 6th grade. It sat around with my parents not wanting to touch the subject and I threw it in the garbage one day when they weren't home. They never said a word about what happened to the book.
To me that sums up the problem. So many parents are just too shy about sex to educate their kids.
Ignoring sex ed and at nearly the same age giving a kid a phone to take to bed with unlimited porn is utterly insane.