Almost 60,000 people in the United States with end stage renal disease are waiting for a kidney transplant. Because of the scarcity of organs from deceased donors live kidney donors have become a critical source of organs; in 2001, for the first time in recent decades, the number of live kidney donors exceeded the number of deceased donors. The paradigm used to justify putting live kidney donors at risk includes the low risk to the donor, the favorable risk-benefit ratio, the (...) psychological benefits to the donor, altruism, and autonomy coupled with informed consent; because each of these arguments is flawed we need to lessen our dependence on live kidney donors and increase the number of organs retrieved from deceased donors. An "opting in" paradigm would reward people who agree to donate their kidneys after they die with allocation preference should they need a kidney while they are alive. An "opting in" program should increase the number of kidneys available for transplantation and eliminate the morally troubling problem of "organ takers" who would accept a kidney if they needed one but have made no provision to be an organ donor themselves. People who "opt in" would preferentially get an organ should they need one at the minimal cost of donating their kidneys when they have no use for them; it is a form of organ insurance a rational person should find extremely attractive. An "opting in" paradigm would simulate the reciprocal altruism observed in nature that sociobiologists believe enhances group survival. Although the allocation of organs based on factors other than need might be morally troubling, an "opting in" paradigm compares favorably with other methods of obtaining more organs and accepting the status quo of extreme organ scarcity. Although an "opting in" policy would be based on enlightened self-interest, by demonstrating the utilitarian value of mutual assistance, it would promote the attitude that self-interest sometimes requires the perception that we are all part of a common humanity. (shrink)