It's a fantastic book which was shortlisted for the Guardian Children's prize and has just won the the Booktrust Teenage Prize. The controversy has arisen because the word 'paedophile' is used a couple of times in the book. However, I hasten to add that THIS IS NOT A BOOK ABOUT PAEDOPHILES. One of the reviewers on Amazon was worried about this but didn't even read the book! This is a unique story about a brother and sister who go on a road trip across Canada and America to find 'family'. Read it first if it would make you happier but please do not write it off because of those reviews.
P.S I have no connection to the author - I just really enjoyed the book.