Dr. Sanjay Gupta examines the potential benefits of medical marijuana. Over 10 years, Dr. Gupta's reporting on the topic has produced six CNN documentaries and a seventh is in the works. In this episode, the very first of those CNN documentaries. Dr. Gupta travels the world and speaks to experts and patients looking for answers. What does marijuana do to you? What does it do to your kids? In the process of his reporting, Dr. Gupta made some discoveries of his own. This special report originally aired on CNN on August 11, 2013.