In this article Lindegger and Richter focus on two contentious aspects of informed consent. The first is the problem of 'social desirability' whereby participants may consent to take part in research because they wish to impress researchers or to please others in the community. The second is ways to determine whether participants' comprehension of the research is adequate to enable them to make an informed choice.

Other topics that are covered are conflicts that can occur between ethical principles and cultural practices when consent to research is sought, and how decisions about whether or not to take part in research should be made by communities and individuals. While consideration of these issues takes place within the context of South African HIV vaccine trials, the issues raised and the useful discussion that follows have a much wider relevance.