Apparently, there are very, very few.
This question came up for me because yesterday I was in the middle of writing a scene in my young adult novel that's fraught with sexual tension. Something funny (and vampiric) happens which causes our heroine to flee from a make-out session with the hottie Witch boy. He thinks she's off to go, you know, find some condoms. She, meanwhile, is trying to put her fangs back in the box, as it were. Hilarity ensues.
I wrote this thinking, "ha! Great scene! Good job, me!" Then, I paused. When I was a teen (back before written record) this sort of thing would have been completely taboo. It would have caused parents, schools, the media, the Congress of the United States... to freak out.
So, like any modern writer seeking answers to such things, I got on the Internet. I posted a question about it on Facebook. I asked a group of SF/F writers (some of which are writing young adult books). I said, "Can I mention condoms in YA? Is it taboo?"
To a person, they scoffed at me. No, no, I was told. Hardly anything is taboo these days. Mentioning condoms is _so_ not taboo that if the possibility of sex between teens is on scene then the RESPONSIBLE thing is to mention condoms!
Someone also pointed me to this great site: Ally's Diary. Ally is Ally Carter a teen author of teen books. She's the insider's insider being both a YA author and an ACTUAL TEEN. Specifically, she's got a great post about this (and a few other things) called, "Wrong Questions... Which I now pass on to you as a great resource for this kind of wrong question... which us forty-somethings trying to write for the modern teen audience seem to always have.
I mean, that's the thing, isn't it? My own experience of being a teenager was long before cell phones, texting, yes, even computers. (Not just the Internet, kids, but computers themselves.) What was taboo for me and my generation seems, well, like child's play to this.
Plus, I don't remember even having a catagory called YA when I was a teen. There was the children's section of the library and the adult section. It seems, in a lot of ways, it's still the same... only with better marketing.
*x-posted from Wyrdsmiths.