My own stomach was already as flat and taut as it had been before I got pregnant. I can thank my mother for that. Good genes—that’s what people have always said about me. They’re talking about the fact that I am tall and thin, that I have a nearly symmetrical face. What they are not talking about are the other genes I’ve inherited. The ones bestowed to me not by my equally symmetrical mother, but from my exceptionally bipolar dad.

