Hippocrates suggested the revolutionary idea that diseases had a cause, and were not sent from God. A diagnosis based on a genetic abnormality may be the modern version of the chronic disease was sent from God. Paul Ewald, PhD, an evolutionary biologist, argued if genes caused chronic disease then the chronic disease would be eliminated or reduced in every generation, because all chronic diseases have a genetic cost. Doctors today may attribute chronic disease to a genetic abnormality; however, genetic abnormalities can also have a root cause. Genes and gene expression are changed by immortal bacterial and viral infections.