How can I determine if the breast cancer in my family is hereditary?

Important factors in determining if the breast cancer in a family is hereditary include: the age of onset of breast cancer; the presence of certain other types of cancer in a family; and the number of relatives with cancer and their relationship to you. A genetic counselor will look at your family's medical information (called a pedigree) including the medical information on first-degree relatives (parents, siblings and children), second-degree relatives, (grandparents, aunts and uncles) and third-degree relatives (cousins).

Hereditary Cancer and Genetic Testing