In 1997 a debate broke out about the ethical acceptability of using placebo as a comparative alternative to establishe effective treatment in trials conducted in developing countries for the purpose of preventing perinatal HIV-transmission. The debate has now been going on for more than five years. In spite of extensive and numerous attempts at resolving the controversy, the case seems far from being settled. The aim of this paper is to provide an updated account of the debate, by identifying empirical (...) arguments employed in the controversy and by critically assessing their use in the debate. A notion of resolution of moral conflicts will be introduced that makes it possible to give a more positive verdict on the moral results of this controversy. Finally, the procedural problem of safe-guarding the selection of empirical arguments against undue forms of normative bias will be addressed. (shrink)