"Data Trends" reports present summaries of research on mental health services for children and adolescents and their families. The article summarized in this "Data Trends" sought to investigate the effects of parent training programs on fathers. More specifically, it sought to examine previous studies to determine: (1) whether including fathers in parent training enhances children's outcomes; and (2) whether mothers and fathers benefit equally from parent training programs. Results support the belief that father involvement in parent training is beneficial, although changes in child and parent outcomes were not as strong for fathers as they were for mothers. Programs that included both fathers and mothers had a stronger effect than those just including mothers. However, programs did not seem to have many long-term effects overall, affecting changes only immediately after program completion: it appears that parent training programs in general would benefit from booster sessions to better support families. [This "Data Trends" presents a summary of: Lundahl, B. W., Tollefson, D., Risser, & Lovejoy, M. C. (2008). A meta-analysis of father involvement in parent training. "Research on Social Work Practices," 18, 97-106.]