The purpose of this study was to examine whether child temperament, parent personality, and the interaction between the two would predict anxiety/depressive problems, and also whether the presence of positive factors would be related to child anxiety/depressive problems. It was also hypothesized that child mood would be predictive of symptoms of anxiety and depression, even after accounting for heritability. Participants were 106 5-year-old twin pairs and their parents, who completed questionnaires and a parent-child interaction. As hypothesized, child negative mood and parent personality were significant predictors of anxiety/depressive problems. However, their interaction was not significant. For children in the negative mood group, as their level of family conflict decreased, their score on anxiety/depression also decreased, providing evidence that low family conflict is protective. Results also revealed that anxiety/depression is heritable and that child mood was significant in predicting symptoms of anxiety and depression even after first accounting for heritability.