It started as blood-typing and has advanced to designing cancer treatments specific to the cellular makeup of a tumor. And in the not-so-distant future, it will mean looking at a patient's DNA to determine the best course of treatment for a variety of diseases. In a program that originally aired last November, Ben talks with guests about the technology that allows doctors to use the right medicines for the right patients at the right time, and the ethical and cost considerations of unlocking the secrets that lie on our DNA.