Sibling Relationships

Siblings are family members who are ascribed by birth (full siblings), by law (adopted siblings) or by marriage (half-siblings, step-siblings, and siblings-in-law). Full siblings have two biological parents in common, whereas half-siblings have one biological parent in common. Legal siblings and step-siblings have no biological parents in common, but their parents are married. A sibling-in-law is related to one’s spouse rather than one’s parent, in any of the previous ways mentioned. A sibling-in-law can also be the spouse of one’s siblings. Social siblings are friends or non-sibling relatives who are transformed into siblings informally, or, in some cultures, through a formal ceremony.

Research on siblings in old age has been limited primarily to full siblings. Important exceptions are the General Social Survey (GSS), which uses nationally representative samples, and the National Survey of Families and Households (NSFH), based on data collected in 1987 and 1988. Both studies include data on step-siblings. Only the NSFH includes data on siblings-in-law (siblings of one’s spouse and spouses of one’s siblings). Neither study has data on social siblings.

Many questions arise when considering siblings among older adults, including: (1) Do older adults usually have living siblings? (2) How many living siblings do they typically have? (3) Can future older adults expect to have living siblings? (4) How important are siblings to older adults? (5) What do siblings do for one another in later years? (6) What factors influence what siblings do for each other and how they feel about each other?