I'd think twice before including, say, The Kama Sutra.
Please read the question before objecting on principle: it specifies high school library.
On the flip side, I'm interpreting "ban" loosely, in the sense of "if I had a job purchasing books for a high school library*, I would probably not choose to purchase this item for the shelves."
Oh, I also might question the wisdom of including the private collection of Rupert Giles on the shelves of a high school library. You know, the "don't speak Latin in front of the books" books.
*This would, in fact, be a job I would love.