In a recent article in this journal, we argued that living organ donation from a parent to a child should be described as a beneficent rather than an altruistic act. Emotional relationships can generate an obligation of beneficence to help those with whom we have these relationships. This may involve an obligation for a parent to donate an organ to a child, even though it entails some risk to the parent. The parent's donation is not altruistic because altruistic acts are not obligatory but optional, and they are motivated solely or primarily by other-regarding concerns. In contrast, donor parents' other-regarding concerns are inseparable from their own self-regarding concerns. An individual who donates to a stranger is acting altruistically. She may choose to help others to whom she is not emotionally related for a variety of reasons—sympathy, compassion, generosity, or a desire to give something back to humanity. But she does not have an obligation to do so. Although she may benefit as a consequence of donating, this is not her reason for donating. Instead, her action is motivated by a concern for the recipient's own sake. This is what makes the donation altruistic, and it can be justified without any expectation of benefit to the donor. However, although the potential competent donor decides whether the donation is in her best interests, physicians have the right to refuse to perform a transplant if the risks to the donor are too great or the potential benefits to the recipient are too small.