The study group consisted of 492 subjects, male and female, but predominantly male, between the ages of 11 and 19 years. The offenses varied from minor ones, such as riding a bicycle without lights, to serious crimes such as rape, arson, armed robbery, sexual assault, and attempted murder. In 397 cases, it was their first offense, and in 86 cases, there had been two or more previous convictions. The control group consisted of a hospital population of mentally handicapped, of the same number, matched for age and sex. Among the proband control groups, nine aspects of the personal and domestic environment were studied: number and nature of offenses; legitimacy of subject; evidence of an indictable offense, prison record, or criminality in the father or maternal parent; evidence of alcoholism in the father or mother; pesonal relationships in the home; and paternal work record. Data were limited by information that was not available in some cases or that may have been withheld. Because of these limitations and because social workers might have differing standards on alcoholism or bad relationships, it was felt that the information was unsuitable for detailed statistical analysis. It was concluded that education for young couples approaching marriage might help offset later delinquency problems, since parental patterns of domestic routine affect children's behavior patterns later. Tables and eleven references are included.