Developmental toxicology is the study of how environmental, chemical, and physical agents affect the development of a fetus or embryo. It is an important branch of toxicology that focuses on the prenatal period and the effects of chemical, physical, and environmental agents on the developing embryo or fetus. Developmental toxicology is concerned with the potential effects of a wide range of agents on the developing embryo or fetus. These agents may include drugs, pesticides, solvents, metals, and radiation. They can enter the body either through ingestion, inhalation, or direct contact with the skin.