One of the many important ethical issues raised by health care systems is how best to sustain equity. As conflicting individual interests are inevitable within a health care system, issues of fairness are bound to arise. Changes in the structure of a health care system are thus key events that can affect equity in important ways. Using the "Benchmarks of Fairness" approach, we assessed the possible effects of introducing selective contracting of physicians on the equity of the Swiss health care system. This approach yields a number of open questions that need to be further addressed if this proposed reform is to be implemented without diminishing the fairness of health care financing and delivery in Switzerland.