Agriculture, industry and medicine are being altered by new biotechnologies. Biotechnology education is important because today's students and citizens will make decisions about the development and application of these new molecular biologies. This article reports an investigation of the teaching of biotechnology in an Australian state, New South Wales (NSW). In NSW few students were electing to answer examination questions related to biotechnology, suggesting that few students were studying the topic. This study looks at why electives relating to biotechnology are chosen or not chosen by students and teachers, with the intention of developing a greater understanding of the requirements for provision of a successful unit of study in this subject. Data was obtained through a survey of secondary science teachers, interviews with teachers and two case studies of the teaching of a biotechnology unit. Teachers reported a range of obstacles to the teaching of biotechnology including the difficulty of the subject matter and a lack of practical work that was suited to the content of the teaching unit. If biotechnology is worth learning in school science, then further research is needed to identify ways to promote the effective teaching of this topic, which teachers regard as important for, and interesting to, students but which most teachers choose not to teach.