A man calling himself Henry Hemp inhales marijuana using a vaporizer pen at HempCon medical marijuana show, May 24, 2013 at the Los Angeles Convention Center. Thousands of marijuana enthusiasts gathered for the three-day event for exhibits of medical marijuana dispensaries, collectives, evaluation services, legal services and equipment and accessories. Under California state law, people suffering from chronic diseases have the right to grow, buy and use marijuana for medical purposes when recommended by a doctor. In 2003 the Medical Marijuana Protection Act, established an identification card system for medical marijuana patients. AFP PHOTO / ROBYN BECK (Photo credit should read ROBYN BECK/AFP/Getty Images)
