The present study investigates how students draw on norms, knowledge claims and authorities when reasoning about socioscientific issues. The aim of the study is to provide an image of students' sense of agency and how they handle trust and security issues by referring to the above mentioned modalities of the societal structures ‘Legitimation’ and ‘Domination’ (Giddens 1984). Examples from gene technology were used as the subject for interviews with 13 Swedish high-school students (year 11, age 17-18). At the time for interviews, the students had participated in and completed an introductory course in genetics which included a group discussion about genetic diseases and ethics. A grid based on modalities from the societal structures described by Giddens was used for analysis of interviews. Students were found to use both modalities for ‘Legitimation’ and ‘Domination’ to justify acceptance or rejection of new technology. By doing that, they showed how norms as well as knowledge claims can be used to justify opposing position as they were trying to build trust in either science and technology or in experts. It was found that students accepted or rejected the authority of experts based on their having or lacking appropriate knowledge. Students were also found to have difficulty in discerning between material risks (reduced safety) and immaterial risks (loss of norms). Attention is drawn to the problem of students' using knowledge claims (Domination) to support norms (Legitimation). Furthermore, students' sense of agency appears to be dependent on sharing norms with experts.