The decision to recommend bilateral prophylactic mastectomy (PBM), one treatment modality used to reduce the development of breast carcinoma, may be influenced by physician bias. This investigation tested the hypothesis that there are physician-in-training biases in recommendations of PBM. All second-year medical students, general surgical residents, and internal medicine residents at our institution participated in a survey in which they were asked at what percent risk of developing breast carcinoma the physicians-in-training would recommend PBM for 1) their patients, 2) themselves, and 3) their significant others, as applicable. A total of 198 physicians-in-training responded. Univariate analysis demonstrated an association between both the type of physician-in-training (p<0.03) and gender (p<0.004) with the percent risk for which respondents would recommend PBM. However, with multivariate analysis, only gender was associated with percent risk (p<0.05). Physicians-in-training also chose PBM at a lower risk for their significant others than for themselves (67.5% versus 57.2%; p<0.02). Respondents also chose PBM at a similar risk for themselves or significant others as for their patients (r=0.83, r=0.98; p<0.001). This investigation suggests that males (compared to females) are more likely to recommend PBM for the prevention of breast cancer.