Here - Tilburg University

Friendships under study were formed when adolescents were around 12 (Wave
I), so we assume their formation is exogenous to the decision to have a child. At
Wave III, each respondent had to indicate from a list of 10 previous school
mates and friends (at Wave I), those who are current friends and those who are
not. In this way, we can distinguish dyads of friends from those of people who
simply share a common social context (they went to school together). By
including these two types of ties in our analysis, we can separate true cross-
friend interaction from contextual effects. Moreover, to distinguish selection from
influence (people might remain friends with those who share similar family
attitudes), we engage in a simultaneous equation model, in which we estimate
together the probability of being current friend with the other person in the
dyad, and one friend’s risk of becoming parents, using as exclusion restriction
the geographical distance between the two friends.
Results show that net of contextual and selection effects, a friend’s childbearing
positively influences an individual’s risk of becoming a parent. We find this effect
being strong in the short-term and inverse U-shaped: it increases and starts to
become significant one year after the friend’s childbearing, it reaches its peak
24-36 months later and then decreases.