This is a sincere and ably conducted study of all the known cases of 'sex offense' which boys (who were not feebleminded) presented to the Children's Courts of New York City during a six year period, 1928 to 1934. It should at once be noted that excessive masturbation and even peeping are included under the term 'sex offense'. Two hundred and fifty-six cases were recorded. They were classified as: group A, one hundred and eight cases appearing before the court exclusively as sex offenders; and group B, one hundred forty-eight cases appearing for various other typical offenses, some of whom (the number is not stated) were also charged with sexual misbehavior. The most frequent offense was sodomy, occurring in a little more than forty per cent in each group. Other offenses did not differ markedly in the two groups except for incest with sisters which occurred in twelve cases of group B (two of the girls becoming pregnant), and in only one (an attempt) in group A. After