This course considers the normal development of the human embryo from the earliest stages to birth. A review of reproductive physiology is followed by a description of the earliest stages of embryonic differentiation and the development of individual organ systems. The course focuses on the stages, developmental mechanisms, and organ systems with greatest potential for improving our understanding of the pathophysiology of congenital abnormalities and malformation syndromes. The role and timing of teratogens, the intrauterine environment in abnormal development, and the contribution of genetic factors are all considered. Through detailed examination of several complex malformation syndromes, students gain insight into the consequences of disrupting the normal synergy between different organ systems during development.