New research has discovered some abnormal genes that are associated with an increased risk of breast cancer and these genes can be passed down from mother to child. But just because you have the gene does not mean you will get breast cancer. Only 1 in 10 women with breast cancer have an abnormal gene.
Breast cancer due to an inherited gene abnormality tends to happen at an early age (under 40), in multiple relatives, and in one or both breasts (but usually not at the same time). The abnormal gene is also associated with an increased risk of ovarian cancer.
But, the truth is the majority of women who get breast cancer do not have breast cancer in their family.