SUBPLOT SPOILERS AHEAD
I think that there's a real problem in the world when a girl who is an upperclassman in high school making a considered decision to have sex once with someone she likes is considered "sensationalizing promiscuity" just because the girl does not regret her decision. I mean, there are even other characters who make a different choice. Plus, as I've hinted at, it isn't even the damn main plot arc of the book.
I'm against censorship in general, but anyone promoting the notion that teens are just oblivious to sex, drinking, or (gasp!) lying to their parents until they read some dirty dirty book about a teen who has sex once and sneaks out occasionally and is sometimes in the vicinity of alcohol is either being deliberately disingenuous or just mind-bogglingly stupid.
Ockler has an awesome response here, but this is my favorite part.
Not every teen who has sex or experiments with drinking feels remorseful about it. Not every teen who has sex gets pregnant, gets someone pregnant, or contracts an STD. Not every teen who has sex does so while in a serious relationship. Not every teen who has sex outside of a relationship feels guilty, shameful, or regretful later on. And you can ban my books from every damn district in the country — I’m still not going to write to send messages or make teens feel guilty because they’ve made choices that some people want to pretend don’t exist.
I can't put Twenty Boy Summer on the official list due to the fact that it does have a couple of occasions of talking about fat as a bad thing that to my mind are completely gratuitous. It's not that the conversations in which this occurs are atypical of teenagers (or most people in our society), it just doesn't do anything to develop a character or move the plot forward. It's not especially vicious or anything, but it's there. It's enough if you're having a fragile day.
Otherwise though, it's a fun and emotional read with well developed characters. I would especially recommend it if you wanted a book that talked about the concept of virginity in a sensible way. And, it's a good example of a girl character being proactive about her sex life while still representing the complex emotions that guide that decision making process for a lot of teens. But again, read the cover blurb because that's not even what it's about.