A recent post on Facebook by a mother asking for advice about handling her twins’ constant arguing generated more than one hundred comments. I read through most of the responses, looking for recurrent themes, thoughts, or threads. Curiously, a number of adult twins wrote that fighting among twins is normal and not to worry. Parents posted concerns about biting, hitting, verbal and physical aggression, and incessant bickering. The post prompted me to reread a book published more than fifteen years […]