To the Editor.—
Recently, a select committee called by the National Institute of Neurological Diseases and Stroke (NINDS) considered the problems of brain research and violent behavior, particularly the implications for "psychosurgery."1 Among other etiologic considerations, this committee dealt with genetic factors, in particular, the XYY genotype and its purported relationship to violence or aggressive behavior. Although the committee included a number of prominent neuroscientists, there was no recognizable expert in human cytogenetics. This may have been responsible for a number of rather sweeping generalizations concerning population cytogenetics, and several unfortunate nonsequiturs and simple factual errors in discussion of the XYY genotype, despite the charge to the participants to "document and evaluate only established facts and to avoid speculation."1 Since the report dealt primarily with issues involving "psychosurgery" and considerations involving the XYY genotype were peripheral to its main considerations, these might well be overlooked were it not