This article describes how a small but vocal group of biomedical scientists propagates the views that either HIV is not the cause of AIDS, or that it does not exist at all. When these views were rejected by mainstream science, this group took its views and arguments into the public domain, actively campaigning via newspapers, radio, and television to make its views known to the lay public. I describe some of the harmful consequences of the group's activities, and ask two (...) distinct ethical questions: what moral obligations do scientists who hold such minority views have with regard to a scientifically untrained lay audience, and what moral obligations do mainstream newspapers and government politicians have when it comes to such views. The latter question will be asked because the 'dissidents' succeeded for a number of years in convincing the South African government of the soundness of their views. The consequences of their stance affected millions of HIV infected South Africans severely. (shrink)