Because young women typically have dense breast tissue, a mammogram is not always the best diagnostic tool for them. For this reason, and because dense breasts also make it more difficult to feel a lump, it is crucial that women aged 20 and older become familiar with their breasts and learn how to spot any unusual changes. Current guidelines call for annual screening mammograms to begin at age 45 or 50. If you have a family history of the disease, consult your doctor about when you should start having mammograms (or other forms of breast cancer screening) and how frequently you should have them. For more information, read our position paper on the new mammography guidelines.