(This program is no longer available for online streaming.) Host Neil deGrasse Tyson submits his spit for analysis in order to get a personal genetic profile that will predict his chances of contracting one of several serious diseases. But would you? Several companies now offer such a service for a fee that can range upwards of several thousands of dollars. How do such tests work and how valid are they? Furthermore, what do you do if you get bad news or good news? Before long, everyone will be able to sequence his or her entire genome. The hope is that doctors may one day be able to use our genomes to predict who is likely to get sick and what to do to prevent it. But this new era will have to wait until scientists fully untangle the web of genetic and environmental factors that cause most human disease.