Debatable donors: when can we count their consent?

Donor consent is the standard requirement for the acceptance of an organ or tissue donation from a living donor. Usually consent to donation is respected as the choice and act of an autonomous agent. There are times, however, when the consent should be paternalistically set aside. The problem for those who must make these decisions is determining when the donor's autonomy should be respected and when paternalistic interference is appropriate. This paper draws on the writings of Kant to develop an autonomy-preserving criterion for determining where to draw the line. It then goes on to display how that criterion could be applied to the case of an adolescent donor who agrees to donate a kidney to his brother.