One of my jobs as youth services librarian is to determine where to shelve different books that come into the library. Often it is difficult to determine whether a book should be shelved in the "juvenile fiction" or the "Teen/YA section" of the library. I try to use 7th-12th grades as a guideline for the teen section...but that is a huge range of maturity and interest...as well as hugely differing ideas among parents as to appropriateness, etc.
Since these books are at a public library, we operate within "intellectual freedom" guidelines that basically say that it is not up to us to determine who can check out what materials...that is a "freedom of information" issue that is protected by the Constitution and applies equally to every library customer, including youth customers. The job of determining appropriateness, therefore, falls to the parents or caregivers of those youth.
The identification of materials as J or Teen or Adult are merely tools to help people find books that will interest them. I think of our young adult/teen collection as one geared toward the interests of those age groups...so sometimes include books that may be considered adult books, but are extremely popular among teen readers. A couple examples would be biographical books of popular musicians, a movie tie-in like Freedom Writer's Diary, or books that have been awarded the High School Book Award (a list that usually combines "teen" and adult books).
Library staff is always willing to give customers more information about content, if asked, so they can determine the maturity level for themselves. However, we can not possibly have this information for every book, nor can we guess or predict what every reader's idea of "inappropriate" or "offensive" could be.
Finally, there are many books in both the Juvenile Fiction sections and the Teen/YA sections that appeal to a wide range of readers, including adults...and I would encourage teens, young adults, and adults of all ages, to not forget to stop upstairs sometimes and browse.
