What is the moral authority of family members to act as surrogates for incompetent patients?

Policy and practice regarding the proper role of family members in acting as surrogate decision makers for incompetent patients often suffer from an incomplete understanding of the diverse grounds of families' moral authority to act as surrogates. The different, sometimes conflicting, grounds of family surrogacy are explored: (1) its establishment by democratic decision processes; (2) the self-determination of the incompetent patient; (3) the fact that a family member usually acts according to the patient's wishes and interest; (4) the reality that family members are usually most affected by the patient's decisions; (5) consideration of these effects; (6) a recognition that the family is a moral unit, responsible for its members. Each of these grounds must be considered when selecting a surrogate or deciding on the proper scope of the surrogate's decision-making authority.