A gene which, when damaged (mutated), places a woman at greater risk of developing breast and/or ovarian cancer, compared with women who do not have the mutation. In a woman with BRCA1 mutation, the estimated lifetime risk of developing breast cancer is about 50% compared with about 12% in the general population. A person who has the mutated gene has a 50% chance of passing on the gene to each of her children. A genetic test is available, but it is recommended only for woman who are known to be at risk because several women in their family have had breast or ovarian cancer at an early age (before menopause). The ACS recommends that any women considering the test receive genetic counseling.