In the Star Trek: Enterprise episode “Dear Doctor” (Season 1, Episode 13), Captain Archer and his crew visit the planet Valakis, where they encounter a species facing a deadly disease. Dr. Phlox discovers that curing the disease would alter the natural evolution of the Valakian species, which raises ethical questions and challenges the crew’s adherence to the Prime Directive. The episode explores the complexities of moral decision-making in the face of interstellar diplomacy and the potential consequences for multiple civilizations.