Handedness in the NIMH [National Institute of Mental Health] monozygotic (MZ) schizophrenic human twins was examined and compared to the report of Boklage. The findings suggest the existence of a subgroup of schizophrenics characterized by abnormal lateralization and a milder form of schizophrenia. It was hypothesized that this subgroup of schizophrenics is not restricted to MZ twins.