Women and men enter graduate programs in biology in about equal numbers, but women are less likely to become academic scientists. Various hypotheses have been suggested to explain this higher rate of attrition, most of which cite family issues as the reason. However, medicine successfully recruits and retains women physicians, despite being less family friendly than biology in terms of workload, stress, and inflexible work hours. Both professions are competitive but at different times in a person's career. Competition for entry into medical school is intense, but this period of competition occurs prior to family formation for most women. For women biologists, the most intense period of competition occurs during the search for faculty positions. Many women have partners or children at this time. The increasing competition for academic positions threatens to reverse the gains that women have made into the professoriate in biology, as well as in other sciences.