Identical twins with nonidentical brains Steven, on the right, has schizophrenia. His genetically identical twin, on the left, does not. Brain scans revealed that Steven’s brain has larger cerebral ventricles than does his brother’s. Such discordance for schizophrenia in identical twins sometimes occurs when one of the two twins (usually the one born second) suffers from lack of oxygen during the birth process and the other does not.
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