Mary-Claire King says obscurity gave her the freedom to spend years looking for breast cancer genes. Mary Levin/University of Washington hide caption

itoggle caption Mary Levin/University of Washington

A technician loads patient samples into a machine for testing at Myriad Genetics in Salt Lake City in 2002. The Supreme Court ruled Thursday that Myriad cannot patent the BRCA genes, which are tested to check a woman's risk for breast and ovarian cancer. Douglas C. Pizac/AP hide caption

itoggle caption Douglas C. Pizac/AP

In sharing her decision to have a double mastectomy, Angelina Jolie has given voice to a dilemma more women are facing. Carlo Allegri/AP hide caption

itoggle caption Carlo Allegri/AP

Mammograms may pose a particular risk to women with genetic mutations that predispose them to breast cancer. Bill Branson/National Cancer Institute hide caption

itoggle caption Bill Branson/National Cancer Institute