Published for secondary school youth in England, the PROBE series presents provocative information and discussion questions on topical themes. The focus of this issue is on aspects of medicine which raise moral dilemmas for doctors, patients, and society in general. This issue contains case studies which illustrate ethical questions raised by the changing role of medicine in society. For each case study, a review of medical practice and issues is followed by discussion questions for students. Legalization of abortions under special circumstances has prompted debate over the status of the fetus and a mother's rights to terminate a pregnancy. Practices of artificial insemination by donor raise questions concerning the donor's right to maintain interest in his child, the mother's motivation, and the "social father's" ability to accept as his own a child whom he did not father. Research on embryo transfers prompts concerns about political manipulation of the process if it is perfected in humans. Issues about euthanasia include a person's right to die with dignity and who has the right to decide if a patient should die. Organ transplants can be life-savers for critically ill people, but when too few donors exist, who should decide which patients will receive donated organs? A concluding section reviews critical questions such as how the interests of the individual relate to those of society, and how medicine should progress. (AV)