Scientific motherhood is the belief that women require expert scientific and medical advice to raise their children healthfully. As it developed in the nineteenth century, women were exhorted to seek out information for themselves. By the twentieth century, women increasingly were told that they continued to be responsible for the well-being of their families, but needed to follow the directions of their physicians. Such instruction positioned mothers as both responsible for their families and incapable of that responsibility. This essay investigates the shifting definition of scientific motherhood and various educational and cultural forums through which women learned this ideology. It also demonstrates that mothers both accepted and resisted the insistence that they depend on instructions from medical practitioners. The history of scientific motherhood is an important lens for studying the complex interrelationship of medicine and social roles.