“Jewish diseases” serve dual roles by enforcing ideas of “racial hygiene” (Sand, 2009) or Eugenics and identifying “cryptic Jews.” For example, mutations in the BRCA1 and other genes leading to breast cancer were initally dubbed “Ashkenazic mutations” and were intepreted as evidence to a shared Judaean or Palestinian past (Ostrer, 2001). This evidence concerns the gene BRCA1 and breast carcinoma.