Data on 10,463 adolescents who participated in the 1999 Youth Risk Behavior Survey (YRBS) were used to analyze the association between individual risk characteristics and sexual activity across early, middle and late adolescence. The cumulative model was used to determine the relationship between the number of risk characteristics and the percentage of sexually active adolescents. In this sample, adolescents in middle and late adolescence were equally likely to display significant individual risk behaviors associated with sexual activity as adolescents in their early adolescence. Moreover, when gender and ethnicity were controlled, the results provided little support for the hypothesis that, (1) Males will display more individual risk characteristics than females and (2), Blacks and Hispanics will display more individual risk characteristics than Whites, no matter what age group. The results support the cumulative risk model that as the percentage of sexually active adolescents increases the number of individual risk characteristics also increases across early, middle and late adolescence.