This age group was selected because this is typically the age when adolescents begin experimenting with "gateway" drugs (cigarettes, alcohol, and marijuana), which are those drugs believed to whet the appetites of youth for drugs with more powerful and harmful effects. Puerto Rican and Dominican students in 22 New York City middle schools participated in the study. Sixth and seventh graders completed self-report questionnaires that measured their use of cigarettes, alcohol, and marijuana at baseline (n=849) and at a 1-year follow-up (n=678). The study found that in the first year of middle school, gender moderated the effect of Hispanic ethnicity on lifetime polydrug use. Dominican boys reported greater polydrug use than Dominican girls, but for Puerto Rican adolescents, drug use was similar across gender. In the second year of middle school, the aforementioned pattern continued, but with more serious levels of polydrug use. These findings support the argument that when examining ethnic differences in drug use, gender should be included; otherwise, ethnic differences might not be accurately assessed; for example, had gender not been included as an independent variable in this study, the findings would have suggested that polydrug use was the same for Puerto Rican and Dominican adolescents. The authors note that a possible reason for the differences in polydrug use based on Hispanic ethnicity and gender is the distinctive migration and historical experiences of Puerto Ricans and Dominicans. American culture may have exerted a stronger influence on Puerto Ricans due to their U.S. citizenship status. 3 tables and 48 references