Evidence that the quality of fetal growth and development has strong and, in widely varying populations, reproducible effects on susceptibility to many common adult human diseases has only been acquired relatively recently. The importance of this largely environmentally determined process in relation to genetic factors remains a topic of great debate. Diseases that have been implicated include cardiovascular disease, hypertension, osteoporosis, schizophrenia, depression, breast cancer, and the polycystic ovary syndrome. This short review focuses on fetal programming of appetite and obesity, coronary artery disease and hypertension, type-2 diabetes, and cancer. The enormous importance of establishing the precise role of environmentally determined poor fetal growth in causing susceptibility to adult disease, usually in combination with adult obesity, (which may itself be a consequence of the same process) is emphasized. Once this is clear, there will be a major opportunity for disease prevention.