Medical students have a wide degree of personal experience of serious illness in themselves and those close to them. In about 4% of cases these experiences have influenced the choice of career specialty. However, formal statistical analysis within a large group of medical students could find no evidence for a relationship. It is suggested that this is due to the inadequacies of statistical methodology, which cannot demonstrate strong relationships in a minority of subjects, when the majority show no relationship. Almost half of the students gave reasons for particular career preferences, but in most cases these appeared to be strongly idiosyncratic.