Are only children missing out? Comparison of the peer-related social competence of only children and siblings

In this study, we tested the assumption that having a sibling provides practice with skills that generalize to peer relations, by comparing the peer-related social competence of only children, first-borns with one sibling, and second-borns with one sibling in a sample of 139 elementary school-age children. Only children were similar to classmates in terms of number of close friendships and friendship quality, but were less liked by classmates as a group. Only children were more likely both to be victimized and aggressive in the peer group, suggesting that having a sibling may be especially helpful for learning to manage conflict. Results are discussed in terms of the need to examine multiple levels of social complexity to understand family-peer links.