Sibling influence on family formation: A study of social interaction effects on fertility, marriage, and divorce.

This study examined social interaction effects on family formation and dissolution, asking whether fertility, marital, and divorce behavior spread in the sibling network. Using panel data from the German SOEP (1984 - 2016; N = 4,521 individuals), we estimated discrete-time event history models with random effects at the individual to examine whether siblings' transitions to parenthood, marriage, and divorce influence an individual's chance to have children, marry, and divorce. Results show that the hazard of becoming a parent increased in the short term after a sibling had a child. Similarly, the hazard of getting married increased following a sibling's marriage. Tentative evidence also suggested that transition rates to divorce increased in the longer term following a sibling's divorce. Furthermore, we found evidence for social interaction effects across different transitions in the process of family formation, as the transition rates to marriage decreased after a sibling divorced. Conversely, the risk of divorce decreased following a sibling's entry to marriage. Overall, these findings illustrate that the impact of network partners on demographic behavior is not limited to the same behavioral domain and might be negative as well as positive.