As the lifespan of a human being has slowly increased over the centuries, a shift in medical focus began to take place. Infectious diseases, once the leading cause of death, began to be tamed by modern vaccinations. This allowed the field to spend more time combating those ailments associated with advanced aging, such as cancer and heart disease. This trend shows no signs of slowing, but rather accelerating. Modern technology permits sophisticated diagnosis and treatment of illness, while at the same time identifying their genetic roots.