In this cohort the best predictors of BC development were having multiple biopsies (OR = 1.40, CI [1.29, 1.53]; p < 10−14), age at joining the clinic (OR = 1.06 per year, CI [1.05, 1.07]; p < 10−28) and being BRCA1 carrier (BRCA1 vs. BRCA2, OR = 1.68, CI [1.33, 2.13]; p = 0.001). The gene discussed is BRCA1; the disease is breast cancer.