<b>Objectives:</b> To gather empirical data on how gender and educational level influence bioethical reasoning among medical students by analyzing their use of care versus justice arguments for reconciling a bioethical dilemma. <b>Setting:</b> University Departments of Medical Ethics, Social and Communication Psychology in Germany. Participants: First and fifth year medical students. Design and method: Multidisciplinary, empirical, 2-segment study of ethics in action: In intrapersonal Segment 1, the students were presented with a bioethical dilemma and then administered a 13-item questionnaire to survey (...) their individual preferences for care versus justice arguments in resolving the conflict. The survey questioned 6 justice, 6 care-related items and 1 socially critical item. Data were analysed by gender and year of medical school. In interpersonal Segment 2, the bioethical dilemma from Segment 1 was discussed in gender-mixed and gender-homogeneous groups. Coded transcripts were evaluated to identify prevalences in care versus justice reasoning. <b>Results:</b> Data on 462 medical students were evaluable (n=338 in Segment 1, n=168 in Segment 2, n=44 overlap). Gender and level of education had no effect on moral reasoning in intrapersonal Segment 1, but significantly affected reasoning in interpersonal Segment 2, where women significantly tended to use more care-orientated arguments. Justice arguments predominated the group discussions. <b>Conclusion:</b> Interpersonal contexts affect moral reasoning in medical students, probably by amplifying the socialisation relating to gender and educational level. Care orientation is associated with the female gender. Professional socialisation tends to reduce the diversity and richness of moral reasoning towards a more justice-weighted orientation. Medical ethics should teach both justice and care reasoning modes in order to broaden physicians' ability to reconcile bioethical dilemmas. (shrink)