Although the specific cause of breast cancer cannot usually be determined in an individual patient, there are a variety of factors that have been associated with an increased risk of developing breast cancer. The number one risk factor is age: as a woman ages her risk of breast cancer rises. Other factors that have been associated with breast cancer risk include early onset of menstruation (<13 years) or late menopause, delay in child-bearing (>30 years old) or lack of child bearing, use of hormone replacement therapy (especially progesterone-containing regimens) after menopause, and history of prior radiation to the chest region. Additional risk factors that have been associated with breast cancer include obesity and alcohol intake. Women who have had previous breast biopsies or a previous diagnosis of ductal carcinoma in situ, lobular carcinoma in situ or invasive breast cancer are at higher risk of developing breast cancer. Family history is another important factor to consider in assessing one’s risk of breast cancer. A family history of breast cancer in first (mother, sister, daughter) or second degree (grandmother) relatives, especially if the diagnosis was under the age of 50 indicates a possible increased risk of cancer. In addition, a family history of ovarian cancer increases one’s risk of breast cancer. That said, the majority of patients diagnosed with breast cancer have no family history of breast cancer. Approximately 5-10% of breast cancer is associated with a mutation in a gene called BRCA1 or BRCA2 which is passed down from the mother or father to their son or daughter. The vast majority of breast cancer occurs in women, but annually around 1500 to 2000 men are diagnosed in the US with breast cancer.