J.L. Bell has a post up at Oz and Ends on genre novels. In it he refers to an article by Charles McGrath in which McGrath says genre writers have an "implicit contract with the reader, which is to deliver on the promise that a particular genre entails--whether it’s a murder solved, a cold war plot thwarted, a horror unmasked, a love requited."
Once you eliminate the obvious traditional genre books in children's literature, Bell asks, "are there children's novels that come with no implicit contracts and expectations to fulfill?"
He goes on, "Even the most serious and literary fiction for children is expected to leave readers with a "sense of hope." The young protagonist is supposed to grow and learn valuable lessons about life, at least a little. Does that recurring pattern make children's novels as a whole a sort of genre?"
Bell is right that many people in kidlit believe children's literature should be instructive and improving. I'm not one of them. Adult readers don't tolerate lessons in their fiction. (We have self-help books.) Why should kids?
Writers have a responsibility to create worlds that readers can feel part of and explore, where they can perhaps try out new lives. Perhaps they will learn something about how they feel about various situations. They may share the author's world view, for instance, or they may reject it. By accepting or rejecting, they may change.
The contract children's writers have that makes their work different from that of writers for adults is that they must write about people--children--who are fundamentally different from themselves. That's what they've agreed to do when they've taken on the task of writing a children's book. If children's literature is a genre, it's because the children's writer is expected to create a true child character living in a true children's world with true children's issues to cope with.
All that stuff about teaching them something and leaving them with hope--that's an adult concern.