Now updated! The new edition of this best-selling guide uses science to tackle some of the most important decisions facing new parents-from sleep training and vaccinations to breastfeeding and baby food. When scientist Alice Callahan became a mom, she knew it would mean long nights of rocking and feeding the baby. What she didn't anticipate was the barrage of parenting questions that would send her down rabbit holes of late-night internet searches, claiming even more sleep than her newborn. Is co-sleeping safe? How important is breastfeeding, and how can parents help it go smoothly? When should babies start eating solid foods, and are there ways to reduce the risk of food allergies? Should we be worried about the unpronounceable additives in the vitamin K shot given to newborns or the aluminum found in vaccines? These questions can confound even the most well-informed of parents, and the search for answers may open the door to a deluge of conflicting advice from well-meaning relatives, judgmental strangers on social media, and self-proclaimed internet experts. In this revised and expanded new edition of The Science of Mom, Callahan, a science writer whose work appears in the New York Times and the Washington Post, turns again to the research literature for clarity. She shares the latest information on raising healthy babies and covers additional topics like the microbiome, attachment, dietary supplements, pacifiers, increasing breast milk production, preventing allergies, baby-led weaning, and choosing an infant formula. Written with compassion and nuance, this unique guide recognizes that all families must make their own decisions and gives science-minded parents the tools to evaluate the evidence for themselves.