...THE POWER of genetic information has shaped virtually every aspect of medicine. On one hand, we have learned about diseases and treatments that are now defined by patients’ genomes. Certain genes can predict colorectal cancer with near certainty and, in women, the BRCA mutations, famously discussed by Angelina Jolie, can denote a greater than 80 percent risk of developing breast cancer. We can screen newborns for dozens of genetic diseases and immediately know which diets to avoid giving them or which medications to begin early. Physicians are using genetic markers to better tailor therapies to individual patients. We are certainly entering a new era.