Hereditary breast cancer (HBC) shows extant clinical and genetic heterogeneity. 
Clinically one finds the onset of breast cancer at an early age, an excess of 
bilaterality, and patterns of multiple primary cancer such as combinations of 
breast and ovarian carcinoma in the hereditary breast-ovarian cancer (HBOC) 
syndrome. In addition to HBOC, one sees a variety of putative breast 
cancer-prone genotypes inclusive of hereditary site-specific breast cancer, and 
the Li-Fraumeni (SBLA) syndrome that is characterized by cancers involving all 
three germinal layers including sarcomas, brain tumors, leukemia, lymphoma, and 
adrenal cortical carcinoma in addition to often markedly early-onset breast 
cancer. Breast cancer is also associated with autosomal dominantly inherited 
Cowden's disease and autosomal recessively inherited ataxia-telangiectasia. 
Examples of pedigrees depicting clinical examples of these several HBC syndromes 
are presented in order to describe HBC's heterogeneity. The recent 
identification of the BRCA1 gene in early-onset hereditary site-specific breast 
cancer and the HBOC syndrome has led to new challenges for the genetic 
counselor. We review genetic counseling, which embraces surveillance and 
management recommendations that are responsive to the natural history of HBC and 
address the concept for future development of centers of expertise for HBC in 
the interest of improving cancer control.