Here's something I just copied...
It was once a given that women should get a first mammogram at age 40, but these days, the recommendations vary. The American Cancer Society now says women with an average risk of breast cancer can start mammograms at 45. And the U.S. Preventive Services Task Force suggests waiting until 50. But other groups, such as the American College of Obstetricians and Gynecologists and American College of Radiology and the Society of Breast Imaging, still say to start at 40. How in the hell would any woman know if she's at average risk of getting breast cancer when 75% of women who get have had no family history? I thought I was of average risk, and guess what happened in my 40's?