An Oct. 20, 2011 study of 358,403 Danish citizens – the largest study of its kind to date – concluded that "there was no association between tumors of the central nervous system or brain and long term (10 years +) use of mobile phones."  A July 27, 2011 study found that there was no association between cell phone use and brain tumor risks among children and adolescents.  Numerous other studies published from 2001-2013 have similarly concluded that there is no association between cell phone use and the development of brain tumors.      
Nevertheless, a group of scientists got together in the mid-2000s, calling themselves the BioInitiative Working Group. This group, which largely consisted of wireless radiation researchers, has written a harsh reply as feedback to the reports claiming that posed no health risks. The reply lists a wide range of health effects scientists at the European Commission have unfortunately either ignored or dismissed.