The term “Hygiene Hypothesis” refers to a theory that the increase in allergies and autoimmune illnesses is linked to reduced germ exposure in childhood. Oster explains this hypothesis by suggesting that exposing children to more microbes and germs during their early years helps their immune system properly identify and respond to pathogens without overreacting. The book presents the idea that avoiding excessive cleanliness, especially in the form of hand sanitizers and other hygiene practices, might be beneficial for a child’s immune development. While conclusive proof for the hygiene hypothesis is lacking, Oster notes evidence from laboratory studies and cross-cultural comparisons that suggests a potential benefit to allowing controlled germ exposure. The concept becomes particularly relevant as children age beyond infancy, with Oster advising a balanced approach where excessive germ protection may not be beneficial. The book implies that a certain level of germ exposure could contribute to a healthier immune system in children as they grow.

The term “Mommy Wars” encapsulates the intense and often polarized debates surrounding various parenting choices. It represents the collective societal and interpersonal struggles that parents, particularly mothers, face when navigating these choices. The term reflects the heightened emotions, judgment, and societal expectations that accompany decisions perceived to significantly impact the well-being of young children.