The article describes a compulsory bioethics module delivered to [approximately] 120 biology students in their final year. The main intended learning outcome is that students should be able to analyse and reason about bioethical issues. Interactive lectures explain and illustrate bioethics. Underlying principles and example issues are used to foster thinking skills. Three assessed seminars, each contributing 10% to the final mark, give practice in analysis and reasoning. In the seminars students work in groups of six and productive discussion is fostered through set procedures and demonstrator help. Generic feedback, along with specific feedback, helps to foster thinking skills. This is assessed in an examination accounting for 70% of marks in which students answer questions that test analysis and reasoning, as well as knowledge. Feedback from students indicated positive approval for the opportunity to think. However, it also identified concerns that reflected the unfamiliar demands of the module compared to demands of other modules. The assessments were strong motivators for students to take the module seriously and to improve their thinking skills. The assessments differentiated students of different ability as successfully as did assessment in other modules. Results were consistent with the module fostering thinking and analysis rather than just "learning". (Contains 3 figures, 3 tables and 4 boxes.)