The effects of sibling relationships on social adjustment among japanese twins compared with singletons

Mari Nozaki, Keiko K. Fujisawa, Juko Ando, Toshikazu Hasegawa

Research output: Contribution to journalArticle

3 Citations (Scopus)


This study examined the link between sibling relationships and children's social adjustment by comparing twin siblings and siblings with different ages (singleton siblings), and clarified the role of reciprocity in sibling relationships on children's social development. Mothers of 58 monozygotic twin pairs, 48 dizygotic twin pairs, and 86 singleton sibling pairs reported their children's sibling relationships and social adjustment. This study showed that the effects of sibling relationships on the prosocial behaviors and conduct problems of each child are stronger for twins than for singleton siblings. Moreover, positivity toward one's sibling increased peer problems only among monozygotic twins. The opposite tendency was present among dizygotic twins and singleton siblings. This study suggests the importance for children's social development of having many interactions with siblings and establishing reciprocity in sibling relationships. Moreover, our results suggest that the quality of sibling relationships among monozygotic twins may be different from those among dizygotic twins and singleton siblings.

Original languageEnglish
Pages (from-to)727-736
Number of pages10
JournalTwin Research and Human Genetics
Issue number6
Publication statusPublished - 2012 Dec 1



  • Twins
  • conduct problems
  • peer problems
  • prosocial behaviors
  • sibling relationships
  • singletons

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Obstetrics and Gynaecology
  • Genetics(clinical)

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