Publication Title: Sociological Forum

Pages: 732-755

Abstract: In the midst of widespread fertility decline, I examine the relationship between sibling number and support network composition using multilevel regression on data from 25 countries. A fundamental structural effect of having fewer siblings is that individuals have a smaller pool of available close-kin alters with whom to construct support networks. Consequently, networks of people with fewer siblings should be composed of different sorts of relations. Results confirm that such compositional adjustment occurs in systematic ways. Compared to those with three or more siblings, adults with 0-2 siblings (as separate categories) are more likely to expect support from parents, extended kin, and close friends but not more likely to do so from spouses/partners and children. Single children are also more likely to include neighbors and have smaller-sized and/or impersonal networks. These findings contradict the primacy of familial ties in social support networks. Moreover, adjustment of support networks towards nonsibling ties occurs in culturally expected ways. Those with fewer siblings are generally only more likely to turn to ties for the types of support typically associated with those relations—parents for instrumental and financial support and friends for emotional support. Single children, however, also violate institutionalized expectations of social support by turning to ties for a wider range of social support. The results suggest that continuing declines in fertility could bring about both reinforcement and rearticulation of the sociocultural framing of close personal relationships. Moreover, consistent with recent research, the results show that personal-networks are influenced more by individual-level than country-level factors.