In its recent review of the US Public Health Service Sexually Transmitted Disease Inoculation Study, conducted in Guatemala from 1946 to 1948, the Presidential Commission for the Study of Bioethical Issues identified a number of egregious ethical violations, but failed to adequately address issues associated with the intentional exposure research design in particular. As a result, a common public misconception that the study was wrong because researchers purposefully infected their subjects has been left standing. In fact, human subjects have been exposed to disease pathogens for experimental purposes for centuries, and this study design remains an important scientific tool today. It shares key features with other types of widely accepted research on human subjects and can be conducted ethically, provided certain safeguards are implemented. That these safeguards were not implemented in Guatemala is what made that study wrong, rather than the fact of intentional exposure itself. To preserve public trust in the clinical research enterprise, this conclusion ought to be stated explicitly and emphasised.