Applications of advanced statistical methods to the study of delinquent/criminal careers have led to the modeling of these careers based on concepts of latent classes of individuals. These statistical models, specifically Poisson process models, have led special utility in the study of criminal careers. Yet, these models have not been applied to longitudinal studies of female offending or comparisons with male patterns of offending, in part due to the scarcity of longitudinal samples with sizable female populations. This study explores the issue of latent classes of offenders in samples of both males and females. A focus was placed on the current debate between self-control and social-control theories and its application to cohorts of females. Data from the Second Philadelphia Cohort were used to address the issue. This cohort is especially useful for comparative purposes and contains information on males and females of the city. Individuals were followed from ages 10 until 26 (1968-1984). The analyses showed differing numbers of classes for males and females. Gender invariances and differences in patterns of offending were found. The results are important for future research in the area of delinquent/criminal careers, especially when applied to populations of women. Figures and references