Family medical histories are used to figure out whether it is worthwhile for a woman to be tested for BRCA genetic mutations, which increase the risk of breast and ovarian cancer.
Andrew Brookes/Cultura RF/Getty Images
Breasts deemed "dense" in a mammogram tend to have less fatty tissue and more connective tissue, breast ducts and glands, doctors say. About 40 percent of women between the ages of 40 and 74 have dense breasts.
Lester Lefkowitz/Getty Images