Breast cancer in young women has always carried an ominous prognosis. There has been little evidence that these concerns are unfounded. The risk for developing premenopausal breast cancer is multifactorial. The younger and less developed breasts are subject to endogenous factors such as hormones and growth factors, as well as exogenous agents occurring in environmental pollutants and other chemicals. Most data indicate that genetic mutations, reproduction history, and family history of breast cancer disproportionately affect the risks of breast cancer in the premenopausal woman. More controversial risk factors that have recently received much attention include diet, physical activity, and stress. Many women who are delaying pregnancy to a much later age will pose an increasing demand for attention to a whole new set of issues in the young women. More effort must be devoted to diagnosing and treating young women aggressively, avoiding toxicity to the fetus, and reducing postpartum risk of recurrence. Though the etiological pathway for breast cancer in the young women is quite a winding one, improving prognosis may be as simple as early detection.