Measures of family stability, sociocultural background, and emotional ties to parents in medical students (N = 589, mean age = 22 years) predicted their social support measures, assessed 23 to 39 years later (mean age = 56 years). Father's education and family's involvement in church were positively associated with group participation (number of group memberships), whereas parental loss between the ages of 11 and 20 was negatively associated with group participation; perceived emotional closeness to parents was positively associated with social closeness (number of close contacts providing emotional and instrumental support). Thus, group participation and social closeness were influenced by distinctly different childhood factors.