Recent epidemiologic studies in the United Kingdom have led to the hypothesis that adverse nutritional experiences in utero have a powerful influence on the development of degenerative diseases in adulthood. Poor fetal growth as measured by weight, length, head, chest, and abdominal circumferences is a strong predictor of hypertension, diabetes, hyperlipidemia, alteration in clotting factors, Syndrome X,* and mortality from cardiovascular and chronic obstructive airways disease. The theory of fetal origins of adult disease proposes that early defects in the development, structure, and function of organs lead to a programmed susceptibility, which interacts with later diet and environmental stresses to cause overt disease many decades after the original insult.