Informed consent honors the autonomous decisions of patients, and family consent places importance on decisions made by their families. However, there is little understanding of the relationship between these two medical decision-making approaches. Both approaches exist in Japan as part of its truth disclosure policy. What is the status of family consent in the United States, from which Japan introduced informed consent? This paper compares the situation in the United States with that in Japan, where family consent has been combined (...) with informed consent. It then explains the history of policy development through which family consent was added to informed consent in the United States. Based on this analysis, the paper suggests that the relationship between informed consent and family consent in the United States was established on the basis of a family model that places more importance on trust-based relationships than it does on blood ties. (shrink)