There are many risk factors for breast cancer, and having it in the family is only one of them. New research has discovered some abnormal genes that are associated with an increased risk of breast cancer. These abnormal breast cancer genes can be passed from mother to child.
Just because you have the abnormal breast cancer gene does not mean that you will get breast cancer. Furthermore, 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.
However, the majority of women who get breast cancer do not have a history of breast cancer in their family.