How and When to tell?

I guess my first question would be what is the situation with his biological father? Because that will factor strongly in your son's adoption story and how you approach him. I've always been told that you should make the adoption something that's told to the child from even before they can understand so that it doesn't become shocking or shameful when "revealed". A friend our ours found out she was adopted at her mother's funeral. Someone came up to her and said, "Are you the adopted one, or is that your sister?". You want to be in control of the knowledge you have, or someone else could "slip" and your sensitive son mayl be doubly devastated that he heard this from someone other than you. Good luck.

I agree. You want to tell him as soon as possible before he accidentally hears it from someone else. Be as honest as you can!