The existence of stepsiblings suggests that both adults have been married or in a serious cohabiting relationship at least once before. Consequently, there can be an exponential increase in family relationships and challenges. There may be at least two living parents for each child, at least two sets of extended kin, and children in the stepfamily may reside periodically in other households. Plus, there are at least two stepparents in the family because each adult partner is both a stepparent and a parent.
If two sets of children live together all or most of the time, stepfamilies may have to seek housing large enough to accommodate both sets of children. Accompanying such moves may be shifts in schools, loss of friends and the familiarity of the old neighborhoods, and a host of other stressors added to the transition into stepfamily life. If one set of children, or some children from both sets, live most of the time elsewhere (with their other parent, for instance), then efforts still have to be made to accommodate/incorporate the nonresidential children into the stepfamily household for visits or extended stays.
Stepsibling relationships present challenges, among them financial, interpersonal, and residential complications. When two parents combine their offspring, lifestyle changes for children are highly probable. As we have seen with other dimensions of stepfamily life, researchers and clinicians generally associate increased complexity with increased problems, and stepsibling relationships in complex stepfamilies are no exception. Clinicians have identified a number of potential difficulties when there are stepsibling relationships: sibling rivalry; competition over scarce resources such as parental attention and space; sexual attraction; having little in common; changes in family size; and changes in the child’s position in the family (Rosenberg & Hajfal, 1985; Walsh, 1992). Few researchers have examined these clinically identified issues.
In one study that did address clinically identified issues, however, the researchers found some support for the notion that stepsiblings create more complex family dynamics (Mekos et al., 1996). In stepfamilies with adolescent stepsiblings, compared to non-stepfamilies and stepfamilies in which all children are full or half siblings, there are greater differences in parenting of the children and more problem behaviors (e.g., alcohol and marijuana use). Differences in parenting and sibling adjustment in non-stepfamilies and in stepfamilies in which siblings share a parent were negligible. However, the relation between differential parenting and problem behavior in stepfamilies with full or half-siblings more closely resembled the relation between differential parenting and problem behavior in stepfamilies with step- siblings than in non-stepfamilies. The researchers speculated that adults and children in stepfamilies, regardless of sibling constellation, are more “sensitive to differential treatment of children by adults, so even small differences in parental negativity make a difference in children’s adjustment” (p. 2161). Parents’ differential treatment of children in nuclear family households has to reach a certain threshold of variation to be noticed by family members—in stepfamilies people may be more attuned to noticing differences, even those of minor magnitude. Siblings in nuclear families develop specializations—4! am the pretty one and my sister is the smart one” (Kowal, Kramer, Krull, & Crick, 2002). There is less time for that level of specialization and differentiation to happen in stepfamilies. There is also the possibility that siblings’ identities from the prior household will lead to conflicts when specializations overlap; a child who was “the pretty one” may be threatened if a stepsibling is much prettier, and who also was “the pretty one” in her family.
Differential treatment in stepfamilies may be due to adults showing preferential treatment to their own genetic children, stepparents backing off discipline and rulesetting for stepchildren compared to their own children (Bray, 1988), and adults responding differently to genetic differences in children (e.g., genetic similarity to themselves). Mekos and colleagues (1996) found that the sibling constellation appears to stimulate differential patterns of parental reactions, which in turn leads to diverse reactions from and outcomes for children in the household. Since that study, several researchers have observed that sibling structure complexity, defined as having either half-siblings or stepsiblings or both, is related to worse outcomes for children (Gennetian, 2005; Tillman, 2008). It should be noted, however, that effects are often small (Gennetian, 2005) and that other studies find no effects of stepsiblings (Bobbitt-Zeher & Downey, 2012; Yuan, 2009).
In the eyes of parents and stepparents, stepsiblings get along well with each other (Duberman, 1975; Ganong & Coleman, 1993), although many stepfamily adults recognize periodic conflicts. In our in-depth study of 52 complex stepfamilies, 39 % of the adults perceived normal sibling rivalry between stepsiblings, 33 % saw jealousy, 12 % reported that sharing space was a problem, 12 % felt their children had nothing in common, and 4 % identified competition as a source of trouble among stepsiblings (Ganong & Coleman, 1993).
Although some studies find few differences between stepsiblings and siblings in other family structures (Anderson, 1999), in general, stepsibling relationships are less close than sibling relationships, both during childhood (Ganong & Coleman, 1993) and as adults (White & Reidmann, 1992). This does not suggest that stepsibling relationships are negative and hostile; on the contrary, stepsibling relationships are reported to be characterized by generally positive affect (Anderson, 1999; Ganong & Coleman, 1993) and substantial contact in adulthood (White & Reidmann, 1992). It is unlikely, however, that stepsiblings think of each other as brothers or sisters. When they do have a sibling relationship, it occurs after they share a residence together over an extended period of time.
Decades ago sociologist Marilyn Ihinger-Tallman (1987) outlined several propositions concerning how and why sibling and stepsiblings bonds develop or fail to develop in postdivorce stepfamilies. She speculated that there are normative pressures on stepsiblings to hold affectionate feelings for each other. She hypothesized that stepsiblings were more likely to bond if:
- • they have frequent contact;
- • they share experiences;
- • there are conditions that foster intimacy (e.g., freedom to express emotions and
a lack of competition for resources) and interdependency (e.g., exchanges of
rewards between stepsiblings);
- • they are similar in age, gender, experiences, and values;
- • there are few perceived costs and more perceived benefits to associating together; and
- • there is perceived equality in giving up aspects of their pre-remarriage lifestyle.
These speculations have not triggered much interest by researchers. Most of the propositions have not been tested (see McGuire & Shanahan, 2010). In summary, a number of questions are yet to be answered or answered fully about the relationships between children in stepfamilies. For example:
- • What is the nature of stepsibling and nonresidential half-sibling bonds?
- • Are stepsiblings considered to be “real” kin?
- • How are half-sibling and stepsibling relationships related to developmental changes in children? What effects do half-siblings and stepsiblings have on each other? (Some researchers have addressed these questions, but findings are mixed and more work is needed).
- • Do stepsiblings provide stress-buffering effects, or do they increase stress related to parental remarriage?
- • Under what conditions do half-siblings strengthen emotional ties in the stepfamily?
- • Are there sex differences in adaptation to stepsiblings?
- • How do stepsibling relationships change over time?
- • What kinds of relationships do adult stepsiblings have with each other?
The notion that sibling structure affects stepfamily dynamics holds intuitive appeal, and recent studies have shown the necessity of accounting for family complexity (i.e., sibling relationships) as well as family structure (i.e., adult relationships status and adult-child relationships) in attempts to understand family dynamics (Brown et al., 2015). The relationships between children in stepfamilies, and the effects of these relationships on other family relationships, will be fruitful areas of future inquiry. Researchers interested in relationships between children in stepfami- lies should examine the growing literature on sibling relationships in non- stepfamilies for conceptual and methodological ideas (Whiteman et al., 2011) . Researchers should be cautious, however, about assuming that processes that affect siblings in first-marriage families also affect stepsiblings in stepfamilies (Dunn & Davies, 2001).