Is anyone else out there adopted?

My oldest son is adopted. He is 24 and we have told him since he was little that he was adopted. We even bought a wonderful book, Why Was I Adopted, by Carol Livingstone that we read to him. He has never met his real parents and says he has no desire to do so...maybe because we were always so honest with him. We answered what we could about his birth parents and half siblings so maybe that is why he doesn't feel that need to find his birth parents. Btw, he calls us his "real" parents...after all, we raised him, fed him, took care of him when he was sick and loved him....his other parents are his "birth parents".