While raising a typically developing child can involve several challenges for parents, this process may be even more complex for families in which there is a child with a developmental disability (DD). This qualitative study utilized a family systems framework to explore the
experiences of nine families with regards to examining the effect of parental differential treatment on the quality of sibling relationships when one sibling has a DD, and the other sibling does not. Questionnaires and in-depth, semi-structured interviews (45-60 minutes) that consisted
of open-ended questions were used. These methods were designed using a variety of question types to gain insight about parental differential treatment and sibling relationship regarding their interactions and the type of social play in which they engaged. The data were analyzed using In Vivo and Axial coding to ensure that concepts emerging from the interview data set captured the key elements of what the interviewee described. Overall, both parents and the typically developing child report that having a sibling with a DD is related to both positive and negative features of the sibling relationship. Furthermore, this study demonstrated that when present, PDT may be linked with less loving and fullfilling sibling relationships from the perspective of all participants. The findings support the importance of implementing, introducing, and teaching methods to parents so that they can take an active role in fostering a positive relationship
between their children.