This paper presents an experimental approach for engaging undergraduate STEM students in anticipatory ethical reasoning, or ethical reasoning applied to the analysis of potential mid- to long-term implications and outcomes of technological innovation. The authors implemented two variations of an approach that integrates three key components-scenario analysis, design fiction, and ethical frameworks-into five sections of an introductory course on the social contexts of science and technology that is required of STEM majors. The authors dub this approach Creative Anticipatory Ethical Reasoning, or CAER. Scenario analysis is a strategy emerging from business consulting for grounded analysis of plausible future trajectories to inform planning. Design fiction is a creative hands-on activity that blends science fiction and design prototyping to facilitate critical thinking with respect to the societal dimensions of a plausible future technology. The authors present the following findings: in each of the variations, students demonstrated significant engagement with CAER and a substantive shift in their conception of what constitutes responsible innovation and ethical conduct in science and technology. Specifically, their integration of ethical reasoning with stakeholder perspectives and scenario analysis reframed technologies, from unproblematic solutions for societal problems to socially-embedded forms of life that might diverge from designers' intentions. This suggests that CAER could be a useful pedagogical intervention for expanding students' ethical engagement to consider the potential unintended consequences of technological innovation.