The Map of the Systen of Human Knowledge by James Tadd Adcox

We had a child but it seemed kind of fragile so we had a backup child. After a while Allison admitted that she'd grown to prefer the backup child to our original one. She felt terribly guilty about this. Of course she went to great lengths to conceal her true feelings. No matter what the backup child did, Allison would find something to criticize. If it drew a picture the colors weren't quite right. If it tied its shoes it should've helped tie everyone else's shoes. If it helped an old lady across the street, it was the wrong old lady, or the wrong street. And so on. On the Fourth of July, at a barbecue we were holding for some friends, the backup child presented a dance it had choreographed, involving some really beautiful work with sparklers and, at one point, a back flip. Allison told it that it might as well give up trying to impress anyone. I know it must've killed her to say that, right in front of everybody, but she said it anyway, for the sake of motherhood.