1. The average U.S. woman wears a size 40 D bra. This equates to about 3 lbs total or 1.5 lbs per breast. 2. In most women, the left breast is usually slightly larger than the right. Very few women have perfectly symmetrical breasts. A slight difference in size — up to 20 percent — between the right and left breast is normal. Sudden changes are not, though, and are reason to talk to your doctor. 3. Breasts normally grow for about two to four years after a girl gets her first period. 4. Breast cancer is the second deadliest cancer for women. Lung cancer is the first. 5. Men can get breast cancer too. There will be an estimated 2,190 new cases of male breast cancer in 2014. Peter Criss of the rock group Kiss is a breast cancer survivor. 7. The state with the highest incidence of breast cancer is Massachusetts. According the United States Centers for Disease Control (CDC), there are 139.5 new cases per ...