Unlatched: The Evolution of Breastfeeding and the Making of a Controversy

Since the rise of artificial formula, we have turned a biological process into a never-ending controversy: A mother breastfeeding her three-year-old son on the cover of Time magazine sets off a firestorm. Facebook takes down photos of women nursing, citing the content as “offensive.” The pope weighs in, urging mothers to nurse their children in church or elsewhere “without thinking twice.”

So how did we get here? What are the consequences of surrendering eons of human evolution for a mode of...