Although approximately 50 percent of marriages end in divorce in the United States, living in a family headed by a single parent is usually only a temporary situation for most parents and children. The majority of divorced men and women will eventually remarry. In fact, roughly one-third of divorced people will re-marry within the first year after their divorce. As a result of these multiple marriages, families may take a variety of forms. One form, the blended family, consists of unrelated siblings (i.e., stepsiblings) from either the mother's or father's previous marriages or romantic relationships, who are brought into a new family when parents cohabitate or remarry. Family members' adaptations to the new relationships in their stepfamily evolve over time and are influenced by a variety of factors.
Hetherington, E. Mavis, Sandra Henderson, and David Reiss. Adolescent Siblings in Stepfamilies: Family Functioning and Adolescent Adjustment. Monographs of the Society for Research in Child Development 64, no.4, serial no. 259 (1999).
Wilson, B. F., and S. C. Clarke. "Remarriages: A Demographic Profile." Journal of Family Issues 13 (1992):123-141.