Parents are usually appreciated as possessing legitimate moral authority to compel children to make at least modest sacrifices in the service of widely shared values of moral decency. This essay argues that such authority justifies allowing parents to authorize a child to serve as an organ or tissue donor in certain circumstances, such as to authorize bone marrow donations to save a sibling with whom the potential donor shares a deep emotional bond. The approach explored here suggests, however, that at (...) least under some conditions, parents have legitimate authority to authorize donations forbidden by current guidelines. (shrink)