Does the ethical appropriateness of paying donors depend on what body parts they donate?

The idea of paying donors in order to make more human bodily material available for therapy, assisted reproduction, and biomedical research is notoriously controversial. However, while national and international donation policies largely oppose financial incentives they do not treat all parts of the body equally: incentives are allowed in connection to the provision of some parts but not others. Taking off from this observation, I discuss whether body parts differ as regards the ethical legitimacy of incentives and, if so, why. I distinguish two approaches to this issue. On a "principled" approach, some but not all body parts are inherently special in a way that proscribes payment. On a "pragmatic" approach, the appropriateness of payment in relation to a specific part must be determined through an overall assessment of e.g. the implications of payment for the health and welfare of providers, recipients, and third parties, and the quality of providers' consent. I argue that the first approach raises deep and potentially divisive questions about the good life, whereas the second approach invokes currently unsupported empirical assumptions and requires difficult balancing between different values and the interests of different people. This does not mean that any attempt to distinguish between body parts in regard to the appropriateness of payment necessarily fails. However, I conclude, any plausible such attempt should either articulate and defend a specific view of the good life, or gather relevant empirical evidence and apply defensible principles for weighing goods and interests.