Objective: To determine under what conditions lay people and health professionals find it acceptable for a physician to breach confidentiality to protect the wife of a patient with a sexually transmitted disease .Methods: In a study in France, breaching confidentiality in 48 scenarios were accepted by 144 lay people, 10 psychologists and 7 physicians. The scenarios were all possible combinations of five factors: severity of the disease ; time taken to discuss this with ; intent to inform the spouse about (...) the disease ; intent to adopt protective behaviours ; and decision to consult an expert in STDs , 2×2×3×2×2. The importance and interactions of each factor were determined, at the group level, by performing analyses of variance and constructing graphs.Results: The concept of breaching confidentiality to protect a wife from her husband’s STD was favoured much more by lay people and psychologists than by physicians . The patient’s stated intentions to protect his wife and to inform her of the disease had the greatest impact on acceptability. A cluster analysis showed groups of lay participants who found breaching confidentiality “always acceptable” , “depending on the many circumstances” , requiring “consultation with an expert” and “never acceptable ”.Conclusions: Most people in France are influenced by situational factors when deciding if a physician should breach confidentiality to protect the spouse of a patient infected with STD. (shrink)