DENVER (AP) -- A Colorado bill that defaults all driver's license applicants as organ donors is unlikely to become law this year. Democratic Sen. Lucia Guzman told Denver's KUSA-TV that she is dropping her proposal that the state change to a "presumed consent" system. That system automatically classifies all applicants for driver's licenses and state ID cards as organ and tissue donors unless they opt out. Such donations are used in several European countries but have raised ethical concerns in the U.S. The Colorado proposal was introduced last week and sparked fears and opposition from many. Supporters say they will drop the proposal for now.