The acceptance of public participation in science and technology governance in liberal democratic contexts is evident in the institutionalization of a variety of mechanisms for participation in recent decades. Yet questions remain about the extent to which institutions have actually transformed their policy practice to embrace democratic governance of techno-scientific decision making. A critical discourse analysis of the response to public participation by the Environmental Risk Management Authority (ERMA), the key decision-making body on genetic modification in Aotearoa/New Zealand, in a specific case demonstrates that ERMA systematically marginalized concerns raised by the public about risk management, ethics, and ecological, economic, and cultural issues in order to give primacy to a positivist, technological worldview. Such delegitimization of public perspectives pre-empts the possibility of the democratic governance of science.