According to an important principle of fairness, objective criteria, such as medical need, determine priority of access to
a transplantable organ. Many people are willing to donate an organ to a stranger, and patients seek out these altruistic donors.
Transactions between these parties threaten the principle of equity according to objective medical need. Altruistic donors
should allocate their donated organs through a system that ensures access according to medical need rather than to the donor's
emotional response to a particular patient's plight, identity, or circumstances. No such system exists at present.