In Australia an increasing proportion of active general practitioners (GPs) are women. Overseas research showing differences between male and female GPs in practice style, the reasons patients consult them, or in the nature of the medical conditions they manage has failed to adjust for confounders. In Australia, such differences have never been investigated. This study assessed differences between male and female GPs in terms of their personal characteristics, patient mix, patient reasons for consultation, and the medical conditions they manage. It also considered the extent to which differences are accounted for by the effect of confounders. A secondary analysis was done of data from the Australian Morbidity and Treatment Survey 1990 to 1991 (n = 113,000 general practice encounters). In addition, univariate analysis was followed by multivariate analysis, with adjustments for GP and patient characteristics and (in analysis of conditions managed) for patient reasons for encounter. Significant differences were found in the work patterns and patient mix of male and female GPs. Patients' selectivity in the problems presented to the two groups remained after adjustment for confounders. Female GPs managed more female-specific, endocrine, general, and psychosocial problems even after multivariate adjustment. Although male GPs managed more cardiovascular, musculoskeletal, male genital, skin, and respiratory problems at the univariate level, these differences were no longer apparent after adjustment. Male and female GPs manage different types of medical conditions. Although some differences are due to their patient mix and to patient selectivity, others are inherent to the sex of the physician. Extrapolation of results to Australian general practice suggests that these two groups of GPs could become semispecialized.