Something to be wary of

[Nanook]

Theoretically, there is a risk but practically it is negligible.

Useful things can be dangerous. Most are. The evidence of potentially harmful effects of low level microwave radiation seems to move more and more towards the side of risk and away from the widely held belief that its harmless. The current state of knowledge increasingly shows that NMR scanning/MRI, despite wide spread belief to the contrary, is not harmless. Its point, however, as X-Ray Imaging (to which Marie Skłodowska–Curie would have vouched), is to find and diagnose things more risky than the risk posed by the test. NMR/MRI is in some of its more "useful" applications used with radioisotopes as PET/CT scanning.
Back to the issue of cell phones? Do cell phones pose risks? Statistically the risk at this stage seems to be lower than many other activities. I would not ignore it but I'd also not, at this time, elevate it (yet) to a highly probably risk.
Automobiles, on the other hand, DO pose big risks. Risks to health, environment as well as peace (oil). Nobody seems to talk about controlling.. them.. on the contrary.. now with the current economic crisis hitting the automotive industry many governments are exploring incentives and subsidies to encourage new car purchases!