This review article analyzes 3 developments within the world of health care that involve concomitant changes in the scope of family and the form of family relationships. The first follows from construction of the informed-consent doctrine and its implementation, the second stems from stunning innovations in reproductive technology, and the third involves the increasing significance of genetic information for medicine. The article suggests that an analysis of changing relationships within the world of health care may offer insights about shifts in the meaning of family. As social domains, the world of family and the world of health care have undergone similar transformations during the past half century. Shifts in the foundational assumptions in each domain—that of the family and that of health care—inform shifts in the other domain. Examining the actualization of these shifts can assist scholars and practitioners in guiding discourse and in resolving disputes among family members and among those who populate the world of health care, including clinicians, patients, and patients' family members.