If a woman has one first-degree relative with breast cancer, her risk of developing breast cancer is times what it would otherwise be.

If a woman has one first-degree relative with breast cancer, her risk of developing breast cancer is DOUBLE OR TWICE times what it would otherwise be.

Explanation:

Women that has one or more close relative(s) who've been diagnosed with breast cancer have a larger risk of having the disease.

If a woman had one first-degree female relative (sister, mother, daughter) diagnosed with breast cancer, the risk of that woman developing it is DOUBLED.

If it is a woman brother or father that have been diagnosed with breast cancer, the risk is much more, although researchers are yet to be able to estimate the percent of developing the health condition.

Often times, a strong family history of breast cancer is connected to possessing an abnormal gene linked with more risk of breast cancer, such as the BRCA1 or BRCA2 gene.