Myth: Only your mother's family history of breast cancer can affect your risk.
Fact: A history of breast cancer in your mother's or your father's family equally influence your risk. That's because half of your genes come from your mother, half from your father. But a man with a breast cancer gene abnormality is less likely to develop breast cancer than a woman with a similar gene. So, if you want to learn more about your father's family history, you have to look mainly at the women on your father's side, not just the men.
Information courtesy of BreastCancer.org