From CNN:
Do cell phones cause brain cancer? It may be too early to say for sure. The latency period or time between exposure and recognition of a tumor is around 20 years, sometimes longer. And, cell phone use in the U.S. has been popular for only around 15 years. Back in 1996, there were 34 million cell phone users. Today there are 9-10 times as many.
Interphone is a multinational study designed to try to answer this question. The data showed people who used a cell phone 10 years or more doubled the risk of developing a glioma, a type of brain tumor.
References:
Cell phones, brain tumors and a wired earpiece. CNN.
Cell phones and your brain. CNN.
Mobile phones may increase cancer risk - list of DOs and DONT's of mobile phone use (scroll down the page). Daily Mail, 2011.
How much radiation does your phone emit? Comprehensive chart by CNN http://goo.gl/l0l5q
