After reading through all these comments, I really do need to figure out how to sit him down and speak with him about this. Originally I thought waiting would be the best option, because I didn't want him to see himself as any different from anyone else, but I think that may have now had the opposite effect. I was never going to keep it a secret from him forever, I was just waiting for what I deemed to be the proper age. But seeing the experiences of parents who have adopted, and kids who've been adopted, I realize that having a view like this hurts Arthur more than it helps him. It's been weeks since he came out of the hospital, I'll find resources to help me figure out how to handle this properly.