THE SURVEY REVEALED FIVE SUBJECTS WITH CHROMOSOMAL ABNORMALITIES: TWO WITH THE 47,XYY KARYOTYPE, TWO WITH THE 47,XXY KARYOTYPE, AND ONE WITH THE 46,XY/47,XXY KARYOTYPE. THE CHROMOSOMALLY ABNORMAL SUBJECTS WERE COMPARED WITH A CONTROL GROUP ON SEVERAL DIMENSIONS: AGE, HEIGHT, WEIGHT, BIRTH RANK, DERMATOGLYPHICS (RIDGES ON HANDS AND FEET), AGE AT FIRST CONVICTION, TYPES AND NUMBERS OF OFFENSES, PSYCHOMETRIC TEST SCORES, ELECTROENCEPHALOGRAM (EEG) READINGS, ETC.) OF SIGNIFICANCE WERE THE FINDINGS THAT BOTH XYY SUBJECTS WERE HOMOSEXUAL WITH SCHIZOID PERSONALITIES, AND THAT THE CRIMINAL RECORDS OF BOTH XYY SUBJECTS AND OF ONE XXY SUBJECT INCLUDED ARSON. MODERATE EEG ABNORMALITIES WERE FOUND IN ALL OF THE SUBJECTS WITH ABNORMAL KARYOTYPES. THE INCIDENCE OF XYY INDIVIDUALS IN THE CURRENT STUDY WAS LOWER THAN MIGHT HAVE BEEN EXPECTED IN LIGHT OF FINDINGS FROM SURVEYS OF OTHER, COMPARABLE POPULATIONS. DETAILS OF TEST RESULTS, COMPARISONS WITH OTHER SURVEYS, SUPPORTING DATA AND A LIST OF REFERENCES ARE PROVIDED. (LKM)