Our findings may have therefore advanced the development of a general model for breast cancer risk: hormonal factors, both genetic and reproductive, can play a key role in the genesis of post-menopausal and “sporadic” breast cancer, whereas genes involved in DNA repair, checkpoints, and genetic stability (such as BRCA1, BRCA2, p53, ATM, CHK2) appear to be more involved in predominantly breast cancers associated with family history of disease. The gene discussed is CHEK2; the disease is breast cancer.