This document discusses how exposure to toxic chemicals may be harming human development from prenatal development through adulthood. It notes that scientists can find over 100 industrial chemicals in people's bodies and that exposure comes through food, consumer products, homes and personal care products. The timing of exposure is important, as chemicals can interfere with development during critical windows and have effects that appear later in life. Mixtures of chemicals may cause greater harm than individual chemicals. The document reviews evidence linking chemical exposures to conditions like preterm birth, learning disabilities, obesity, declining fertility and some cancers. It concludes that reducing exposures through policy changes can improve public health outcomes.