The teenage years are the last golden opportunity to build a healthy brain, researchers say. So smoking pot might not be so smart. Tomas Rodriguez/Corbis hide caption

itoggle caption Tomas Rodriguez/Corbis

The legalization of marijuana could dry up a revenue stream for police, according to reports. Here, two men share a water pipe underneath the Space Needle shortly after a law legalizing the recreational use of marijuana took effect in Seattle in 2012. Stephen Brashear/Getty Images hide caption

itoggle caption Stephen Brashear/Getty Images

New York Gov. Andrew Cuomo is reportedly considering allowing the use of marijuana for medicinal purposes. Tim Roske/AP hide caption

itoggle caption Tim Roske/AP

A man uses the Nasal Ranger to detect smells in the southern U.S., in this photo provided by St. Croix Sensory. In Denver, the device is being used to monitor complaints of strong marijuana smells. Courtesy of Nasal Ranger hide caption

itoggle caption Courtesy of Nasal Ranger

An ATM sits next to a rack of marijuana clone plants that are used to grow medical marijuana on Wednesday at The Joint, a medical marijuana cooperative in Seattle. Last week Washington became the second U.S. state to adopt rules for the recreational sale of marijuana. Ted S. Warren/AP hide caption

itoggle caption Ted S. Warren/AP

A man smokes marijuana outside Uruguay's parliament in Montevideo on Wednesday, where lawmakers in the lower house debated and passed a bill that would legalize marijuana and regulate its production and distribution. Matilde Campodonico/AP hide caption

itoggle caption Matilde Campodonico/AP