If a woman has a first-degree relative with breast cancer, such as a mother, sister, or daughter (or a male relative), her risk for breast cancer increases. It also increases if she has multiple family members on either her mother's or father's side who have had breast cancer.
"For women of average risk, I recommend beginning annual mammograms at age 40," Linda Greer, MD, the medical director at HonourHealth Breast Health and Research Centre, told POPSUGAR. "Women with a family or personal history of breast cancer do have a higher risk of developing breast cancer during their lifetime, and so it's advised that you speak with your doctor, as earlier screening may be necessary."
However, she added that if you don't have a family history of breast cancer, you're not in the clear; nearly 80 percent of women who are diagnosed with breast cancer have no family history of the disease.