The work presented here represents a preliminary attempt to address the role of teachers in supporting students' learning on socio-scientific issues (SSI) by characterising pre-service biology teachers' perceptions and adaptation of curriculum and identifying factors that serve to mediate this process. A hundred and two undergraduate pre-service biology teachers took part in this study over the course of one semester. The teacher candidates (72% female) completed a questionnaire comprising Likert-type and open-ended questions. The results indicated that the teacher candidates perceived a need to address SSI positively. Pre-service teachers had moderate personal teaching efficacy beliefs related to teaching about SSI. They also identified the lack of instructional time and the unavailability of relevant materials as the primary obstacles hindering the teaching of SSI. The implications for teacher education and the design of curriculum materials with respect to SSI are discussed. (Contains 4 tables.)