Using panel data, we estimate the impact of an increasing share of female physicians on the total output of Canadian physicians. A micro-econometric model is developed specifically for the Canadian context and estimated using administrative data on all Canadian physicians paid on a fee-for-service basis from 1989 to 1998. Our results suggest that female physicians systematically provide fewer services than their male counterparts for almost all specialties and provinces studied. Given that females account for an increasing share of the physician population and that female physicians provide, on average, fewer services, potentially important future reductions in total health-care service provision are likely.