The hypothesis that schizophrenia results from a developmental, as opposed to a degenerative, process affecting the cerebral cortex has become popular in current thinking about the disorder. While many of the data gathered in support of this hypothesis do not in themselves represent conclusive proof, an intriguing picture is emerging from a variety of research approaches. These approaches include the observation of minor physical anomalies, premorbid neuropsychological and social deficits, obstetrical complications, and exposure to adverse intrauterine events. Morphometric brain measurement techniques and neuropathological studies have perhaps provided more substantial support.