The study found that at 12 years old a gender difference in rumination was observed; and 1 year later, gender differences in stress and depression were noted. These results confirm the study's hypothesis and lend support to the view that early adolescence is a critical time for female adolescents, in that depression and other socio-emotional indexes begin to differ from those of male peers. Nolen-Hoeksema and Girgus (1994) predicted that a gender difference in rumination should precede a gender difference in depression. The cross-sectional findings of the current study apparently support this prediction; however, longitudinal data must be collected in order to verify that increases in rumination precede increases in depression for individuals over time. The current study also predicted that the use of rumination would increase in a linear fashion for females until they were 17 years old, and this hypothesis was largely supported. Male participants were expected to report consistently low levels of rumination use between the ages of 10 and 17, and this hypothesis was also largely supported. The study used a cross-sectional, nonclinical sample of 1,218 adolescents (ages 10-17), who completed measures of stress, rumination, and depression. The sample was composed of 473 boys and 745 girls. 3 figures, 3 tables, and 63 references