BLOOD SAMPLES FOR EACH OF THE 96 PATIENTS WERE TAKEN, AND BLOOD FILMS WERE PREPARED AND STAINED. LEUCOCYTE CULTURES WERE HARVESTED AT 46 HOURS. THESE STAINS AND BUCCAL SMEARS FOR THE SUBJECTS WERE STAINED WITH ACETIC ORCEIN. TWO HUNDRED POLYMORPHONUCLEAR NEUTROPHILS AND TWO HUNDRED BUCCAL MUCOSAL CELLS WERE EXAMINED FOR EACH SUBJECT, AND EACH SUBJECT'S HEIGHT WAS NOTED. RESULTS SHOW THAT ONLY ONE PATIENT, A MALE, WAS TALLER THAN 183 CENTIMETERS AND THAT NONE OF THE SUBJECTS HAD AN XYY KARYOTYPE OR ANY OTHER CHROMOSOME ABNORMALITY. ONE MALE DID HAVE AN UNUSUALLY LARGE Y CHROMOSOME. THE FINDING THAT NO MALES HAD EXTRA Y CHROMOSOMES IS SOMEWHAT SIGNIFICANT IN THAT NONE OF THE SUBJECTS WERE TALL AND TALLNESS IS ASSOCIATED WITH THE XYY KARYOTYPE. TABULAR DATA AND REFERENCES ARE PROVIDED. (DAG)