The Walters family has two sons, aged four and seven. These sweet boys look so much alike that I do a double take each time I see them. Their mom dresses them in matching outfits for holiday photos, and their parents hear a constant litany of how much they resemble each other. But appearance is where the resemblance ends. Having gotten to know these two children, I can tell you that their personalities are nothing alike. Geoff, the elder, is quiet and studious. He’s a rule follower and a bit of