The association between 2D:4D ratio and aggression in children and adolescents: Cross-cultural and gender differences.

<bold>Background: </bold>Two recent meta-analyses have suggested the association between digit ratio (2D:4D) and aggression is weak. This conclusion has been criticised because the meta-analyses conflate forms of aggression that show strong sex differences with those that do not, and most studies have considered post-pubertal participants.<bold>Aims: </bold>We test the influence of 2D:4D and ethnicity in the expression of aggression in children and adolescents in four ethnic groups of European and African origin.<bold>Study Design: </bold>Buss and Perry aggression questionnaire. Direct measurement of the 2nd and 4th digits.<bold>Subjects: </bold>1296 children and adolescents from Tanzania and Russia from 4 ethnic groups - Datoga, Meru, Russians, Tatars.<bold>Results: </bold>There were ethnic and gender differences in ratings on aggression with boys consistently reporting more physical aggression. In all four samples right 2D:4D was significantly lower in boys, compared to girls. With regard to our total sample of boys, the right 2D:4D was significantly and negatively associated with self-ratings on physical aggression, but no association was found for left 2D:4D. No associations between 2D:4D and physical aggression were found for girls. Hostility was negatively correlated with 2D:4D for boys, and anger was positively correlated with 2D:4D in girls.<bold>Conclusion: </bold>Sex differences were strongest for right 2D:4D (boys<girls), and for physical aggression (boys>girls). Right 2D:4D was negatively related to physical aggression in boys only, suggesting possible relationship to prenatal androgenization. [ABSTRACT FROM AUTHOR]