oh great topic!   
My son's full time GT 3rd grade classroom is reading Jacob I have Loved right now.    I just happened to read some of his assigned pages to him late last night since it was well past bedtime and he was so tired.   As I was reading,  I saw a page full of detail coming up about the main character having gotten her period and her body changing that summer.  How she got her period, embarrasment, ruinin her dress, etc.   I promptly skipped over that section but was really annoyed that the teacher would choose that book.   I'm not prepared to have that conversation yet with my 8 1/2 year old son.  I'm not sure if it will come up in class or not.    I know it's tough to find appropriate books for advanced readers but this was surprising to me.
Additional book for the list:
Penn Dragon - started to read the first book and it was way to "teen."    Talked in great detail about the boy making out with a girl and some other stuff that I didn't care for.