I understand if the book contains sex or violence, but to do more than advise of comprehension level needed is ridiculous-- especially for a librarian!
I agree with the violence part I guess. But for sex, I think being exposed to these ideas before I was "ready" prob did me good in terms of being more aware of potential pitfalls. Books tend to explain the emotional side of sex in a way that films just can't, and in this day and age children are exposed to so much digitally that I think a good book with sex in context could be seen as very valuable.
I think latest research in NZ showed kids as young as 11 were exposed to online pornography so I don't think they'd be learning anything new except perhaps the issues surrounding sex. I think these sorts of books are selected by kids who are either at the recommended age or gifted and therefore bring the necessary maturity to decipher the material - or gain it from the reading.
I think a kid who is too young to absorb this sort of material would probably lose interest in the book as a whole before reaching any lewd parts. My 2 cents anyway
