When Christina and I first became good friends 10 years ago, she confided to me that she had always wanted a little sister. (Since I am a little sister and I know how annoying they can be, I remember asking, “Why???”) Minutes later, she decided that I would fill this role and make her dreams of being a big sister come true. When she affectionately told sales assistants and cashiers that I was her sister, they would glance with skepticism at our differing hair color and complexions, at my cane and her scooter, and say, “Really?” We would then explain that we had always felt and acted like sisters, even if there was no biological basis for the relationship. … More Counterparts