I didn’t have a family life. My mother used to sit on my head to make me still so she could beat me with a cord, belt, or anything she could get her hands on, and things got worse when she burned me with an iron, and she allowed certain relatives to have sex with me.

These are the words of “Alma,” an abused child who would grow up to abuse her own son so severely that he would die of his injuries. Alma’s story, quoted by Susan Crimmins and her coauthors in a study of women who have killed children, lends credence to the commonly held view that child abuse is passed on from generation to generation in a “cycle of violence.” In short, the theory goes, people who are abused as children are...