Child gender may exert its influence on development, not as a main effect, but as a moderator among predictors and outcomes. We examined this notion in relations among toddler fearful temperament, maternal protective parenting, maternal accuracy in predicting toddler distress to novelty, and child social withdrawal. In two multi-method, longitudinal studies of toddlers (24 months at Time 1; Ns = 93 and 117, respectively) and their mothers, few main effect gender differences occurred. Moderation existed in both studies: only for highly accurate mothers of boys, fearful temperament related to protective parenting, which then predicted later social withdrawal. Thus, studying only main-effect gender differences may obscure important differences in how boys and girls develop from fearful temperament to later social withdrawal.