If our students are to become well-informed decision makers then they need to be aware of the practical applications of current developments in biotechnology, and appreciate the social and bioethical implications of this relatively new and controversial science. In this study, Year 10 (14-15 year old) science students in two schools were taught biotechnology courses that introduced them to bioethics. At the conclusion of the course, students completed a survey in which they made a decision about three bioethical dilemmas, and gave reasons to support their decision. The students' responses and reasons were compared with those of three experts. Although there was variation amongst students, the results of the survey suggested that the majority of students tended to resolve and justify their decisions in a way that was naïve, idealistic, and rights based. Compared to the experts, the students seemed to give undue emphasis to the bioethical principle of autonomy. In addition, the reasons supplied by many of the students to support their decisions suggested that they did not consider long term consequences. These findings have ramifications for teachers who wish to include bioethical dilemmas in their teaching.