In 2006 I wrote a newspaper article titled “Why I No Longer Believe Babies Should Cry Themselves to Sleep,” pointing out that leaving small infants alone stresses their brains, with potential negative effects. It also hurts a mother’s heart. I quoted my late mother-in-law, Monica, who had a painful memory of being a young mom in the late 1940s and early ’50s and following medical counsel to ignore her infants’ cries. “It was torture for me to do it,” she told me. “It went against all my motherly emotions.”