THE PROBAND GROUP WAS OBTAINED AFTER SEARCHING THE RECORDS AT THE IDAHO WOMEN'S REFORMATORY AND STATE TRAINING SCHOOL. OF THE 41 MOTHERS 91 PERCENT WERE FELONS. A GROUP OF CONTROLS WAS SELECTED FROM THE STATE INDEX OF ADOPTIONS AND MATCHED AS CLOSELY AS POSSIBLE FOR SEX, RACE, AND AGE AT THE TIME OF MATERNAL SEPARATION AND PLACEMENT, ETC. STATE BUREAU OF CRIMINAL INVESTIGATION RECORDS WERE SEARCHED FOR INFORMATION ON THE SUBJECTS, SOME ADOPTIVE PARENTS WERE INTERVIEWED, AND ALL SUBJECTS WERE SUBJECTED TO A STANDARD PSYCHIATRIC INTERVIEW, DURING WHICH A MEDICAL, PSYCHIATRIC, FAMILY AND SOCIAL HISTORY WAS OBTAINED. THE SUBJECTS SELF-ADMINISTERED THE MINNESOTA MULTIPHASIC PERSONALITY INVENTORY. THE FOLLOWUP INFORMATION WAS TRANSCRIBED INTO CASE HISTORIES AND DIAGNOSED. A SIGNIFICANTLY HIGHER RATE OF ANTISOCIAL PERSONALITY WAS FOUND AMONG THE PROBANDS (13 PERCENT) THAN AMONG THE CONTROLS (O PERCENT). THE NONANTISOCIAL PROBANDS PROVED NOT TO BE MORE DEVIANT THAN THE CONTROLS. THE ANTISOCIAL PROBANDS EXPERIENCED CERTAIN UNFAVORABLE CONDITIONS IN INFANCY THAT MAY BE RELATED TO THE DEVELOPMENT OF ANTISOCIAL PERSONALITY, THE MOST NOTABLE BEING THE LENGTH OF TIME SPENT IN TEMPORARY CARE PRIOR TO FINAL PLACEMENT. ALTHOUGH THE CONTROL GROUP WAS EQUALLY EXPOSED TO THE SAME CONDITIONS, THEY DID NOT DEVELOP A HIGH RATE OF THE DISORDER. THE FINDINGS POINT TO THE IMPORTANCE OF INTERACTIONS BETWEEN GENETIC AND ENVIRONMENTAL FACTORS IN THE DEVELOPMENT OF ANTISOCIAL PERSONALITY. TABULAR DATA AND REFERENCES ARE PROVIDED. (AUTHOR ABSTRACT MODIFIED--DAG)