It should be very simple to just not market books with open door sex scenes as YA, it isn’t about pearl clutching. I don’t agree with the idea of book ratings (like movies or games have) or content warnings in books. However, I should also expect books to be marketed appropriately, so that books for every age range won't be FORCED to have warning stickers on them.

Some books have young adult characters, but the books are not thematically appropriate for kids. Yes, YA is for kids. If you want to say “uuuhhhh actually I'm 35 and read YA” that's fine, but YA being for ages 12-18, IT'S FOR KIDS. “UHHH Lisa don't you let your kids watch rated R movies” yes, but while I'm with them, so we can discuss what's going on. (And anyway, we're talking like Terminator 2 rated R, not I Spit On Your Grave (original) rated R.) Reading is a solitary activity. How frequently, do you really think, a parent is reading entire novels before letting their teenager read them? And this is coming from someone who was reading bodice rippers at 13. I should not have been. But guess what, those books were not marketed to 13 year olds, and my mother was not paying any attention to what I was reading. (Or watching, or…)

Can YA tackle tough issues? Of course it can. I read the edgy babysitters club spinoff series where it tackles stuff like alcoholism etc, back in the late 90s. (Series was called California Diaries if you're curious. A rare contemporary series I enjoyed back when I was reading mostly fantasy and YA horror) But they tackle tough issues age appropriately.

Anyway my point is, I don't want censorship or rating systems or mandatory content warnings in books so THINK about your target audience for more than 5 seconds. Trad published books, especially, should know better.