The existing literature shows that the social interactions in personal networks affect individuals' reproductive attitudes and behavior through three mechanisms: social influence, social learning, and social support. In this article, we discuss the extent to which the socio-psychological model of the Theory of Planned Behavior (TPB) takes these social mechanisms into account when used in modeling fertility intentions and behavior. We argue that by integrating all three social network mechanisms, the ability of the TPB to explain reproductive events could be enhanced in two respects. First, social influence explains why some beliefs and practices are reproduced at the individual level even in the face of macro-level changes, and social learning mechanisms are crucial to distinguish who finally adopts new behavioral beliefs and practices in response to changes at the macro level. Second, social support relationships represent a capital of services to complement institutional provision (informal child care) as well as a capital of knowledge which helps individuals navigate in a complex institutional environment,providing a crucial element to explain heterogeneity in the successful realization of fertility intentions across individuals. The integration of the three social network mechanisms into the TPB helps to address the connection between changes in what the theory indicates as background factors and variation in individual intentions and behavior. We develop specific hypotheses concerning the effect of social interac- tions on fertility intentions and their realization and conclude with a critical review of the existing surveys that could serve to test these hypotheses and their limits.