This dissertation thematises what it means to use science knowledge on societal issues from outside science. To this end, the dissertation, first, critically discusses how science education researchers could understand and analyse students’ socio-scientific argumentation. It is argued that socio-scientific argumentation is a type of deliberation process in which arguers manage (potential) disagreement about what to do (not just what is true) by providing arguments and by engaging with the arguments of their interlocutors. This constrains how such discourse should be analysed. Second, the dissertation applies normative pragmatics in an analysis of students’ use of science content in eight socio-scientific group discussions about human gene therapy. The specific focus of the study was on the argumentative role that invocations of science had in the dialectics of the discussions. The analysis suggests that science content occasionally played an informative role in attempts to establish the factual background of parts of the deliberations, but that speakers often invoked science content creatively and selectively in argumentative strategies that aligned with an attempt to frame the issue of the discussion in ways that were favourable for the speaker. The dissertation aims at explaining how such strategies worked pragmatically in the dialectical context of the discussions.