These profiles in turn generate ““customized’’ responses to child-rearing challenges. For instance, if your child is in the ““slow to adapt’’ category and you plan to use a playpen, The Preventive Ounce suggests you introduce it at 4 months and stay within the child’s field of vision during each period of confinement until the child seems comfortable. This will make for fewer tantrums later on, when your baby’s wails may start getting on your nerves.