1. ethical issues relating to the proper limits of a professional relationship between a provider of services (e.g., a physician or a psychotherapist) and his or her patient or client, such that the trust and vulnerability of the latter are not abused (see boundary). A particular area of concern is professional–client sexual relations.

2. in health care, issues relating to the demarcations between different areas and levels of expertise and questions of who is best qualified to give certain types of treatment or advice.