Criminology literature maintains that the level of delinquent behavior differs between males and females, but variations in the extent of difference typically appear in comparisons of self-reported studies and studies using official police records, with the ratio of male to female delinquency being lower in self-report studies. One hypothesis, to explain these diferences, termed the 'chivalry' hypothesis, holds that police are much less willing to make on-the-spot arrests of women. An alternative explanation, termed the 'methodology' hypothesis, argues that typical self-report studies distort the picture by using omnibus scales that may create discrepancy in results that disappears when offense-specific analyses are undertaken. To test the explanatory power of these two hypotheses, 1,131 high school students from an industrial suburb in a major East Coast metropolitan area (predominantly white) were administered a questionnaire on delinquent behaviors that included 19 illegal activities. For each activity, the respondents were asked to indicate the number of times during the preceding year they had engaged in the activity and the number of times they had been contacted by the police for each activity. Of the 1,119 usable questionnaires, 562 were completed by males and 557 by females. Using analysis of covariance controlling for the differences in self-reported delinquency, substantial support is provided for the methodology hypothesis. Tabular data and 14 references are provided.