The debate over when women should have their first mammogram, and how frequently they should have one, is heating up again. The American College of Gynecologists (ACOG) says women should begin using the standard breast cancer test at age 40, and be tested annually. The American Cancer Society, the American College of Radiology, the Society of Breasts Imaging, Susan G. Komen for the Cure, and the National Comprehensive Cancer Network have also come out in favor of annual breast scans, beginning at age 40. But the US Preventive Services Task Force, a federally-supported expert panel, supports beginning mammograms at age 50, and testing every other year.

The Task Force believes that the benefits of starting mammograms at age 40 (a slightly higher rate of breasts cancers discovered and, likely, treated) is far outweighed by negatives. A spokesperson for the Task Force says that half of women in their 40's who have annual mammographies will experience false positive results, which usually leads to additional testing, including unnecessary biopsies.

So when should women begin having mammograms? Most experts recommend basing that choice on advice from their OB/GYN. That advice should consider, among other things, a patient's family's cancer history.