A blog entry in Publisher Weekly got me thinking about this issue, and I thinks it's important enough to comment on, even though it's a contentious subject. I'd agree with Josie: the idea of nine-year-old girls reading Twilight makes me uncomfortable. No bookseller, teacher or parent ever wants to be in a position of telling a young reader not to read a book, but I think the writer of Ecclesiastes had a point: to everything there is a season. Call me a prude, but I'm not sure elementary school is the right season for hot and steamy undead romance novels. (And yes, I've read Twilight.)
Long before Twilight, I had trouble with the one-upmanship around Harry Potter. It was as if families were in a competition to see how soon their children could master those massive tomes. "My first grader read them!" "Oh yeah, well my kindergartner finished the whole series!" "Oh yeah, well my toddler . . ." It just seemed silly to me. Why the hurry? Growing up is not a race. For one thing, it's sad when kindergartners skip over kindergarten books, because they're missing an awful lot of good, age appropriate literature. For another thing, they won't appreciate the older books as much as they would when they're . . . well, older. Some of the content in the older books really is not designed for the very young. I totally understand kids wanting to be part of the newest cool thing. But those books will still be there in a few years, and if they're not as cool anymore, something else will be.
By the same token, I'll admit I have to bite my tongue when a parent comes up to me and says, "My six-year-old loves Percy Jackson." The author part of me says, "Hey, that's great!" The teacher part of me wants to scream, "A six-year-old has no business reading Percy Jackson!" I don't care if they can decode the words. The content simply is not appropriate, in my humble opinion as the guy who wrote the books (and designed them for the middle grades, roughly ages 9-14).
There's an old test we teachers use for determining whether a child is ready for a book. The child is instructed to read a random page in the novel, and put a finger down for every time they stumble on a word. If they stumble five times and make a fist, the book will probably be too frustrating. The problem with this system is that it only measures decoding skills. It does nothing to determine the appropriateness of content. Plenty of kids can read Percy Jackson, or Harry Potter, or Twilight. Should they read those books at their present age? That's another question entirely.
Having said that, I recognize that every child is different. Each reader is ready for different books at slightly different times, but there are developmental stages -- socially, emotionally, cognitively -- and they all have to be considered. I'm never for censorship, as long as book choice is the result of responsible decision-making and engaged parenting. Rather than the 'five finger' method, I usually suggest something much more time-consuming, but much more accurate. When in doubt, the parent should read the book. If it still seems good for your child, then go for it. Have a family discussion about the content. If it seems like a fine idea to you for your nine-year-old to read Twilight or your six-year-old to read Percy Jackson, well . . . I may still disagree with you, but at least I'll know you made an informed choice.