We'll know for sure in twenty or thirty years. Most people put the phone to the same ear repeatedly...in a long conversation they will switch ears. One ear, though, is definitely getting a higher dose. If instances of skin cancer go up for people's "dominate" ear, I would consider that a condemnation of the cell phone. According to the FCC, though, Volo is correct...only high intensity electromagnetic radiation causes tissue damage and almost no cellular damage. http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet56/oet56e4.pdf
At relatively low levels of exposure to RF radiation, i.e., field intensities lower than
those that would produce significant and measurable heating, the evidence for production of
harmful biological effects is ambiguous and unproven. Such effects have sometimes been
referred to as "non-thermal" effects. Several years ago publications began appearing in the
scientific literature, largely overseas, reporting the observation of a wide range of low-level
biological effects. However, in many of these cases further experimental research was unable
to reproduce these effects. Furthermore, there has been no determination that such effects
might indicate a human health hazard, particularly with regard to long-term exposure.
More recently, other scientific laboratories in North America, Europe and elsewhere
have reported certain biological effects after exposure of animals ("in vivo") and animal tissue
("in vitro") to relatively low levels of RF radiation. These reported effects have included
certain changes in the immune system, neurological effects, behavioral effects, evidence for a
link between microwave exposure and the action of certain drugs and compounds, a "calcium
efflux" effect in brain tissue (exposed under very specific conditions), and effects on DNA.
Some studies have also examined the possibility of a link between RF and microwave
exposure and cancer. Results to date have been inconclusive. While some experimental data
have suggested a possible link between exposure and tumor formation in animals exposed
under certain specific conditions, the results have not been independently replicated. In fact,
other studies have failed to find evidence for a causal link to cancer or any related condition.
Further research is underway in several laboratories to help resolve this question.
In general, while the possibility of "non-thermal" biological effects may exist, whether
or not such effects might indicate a human health hazard is not presently known. Further
research is needed to determine the generality of such effects and their possible relevance, if
any, to human health. In the meantime, standards-setting organizations and government
agencies continue to monitor the latest experimental findings to confirm their validity and
determine whether alterations in safety limits are needed in order to protect human health.
I don't know if the FCC is a reputable resource, but they are considered the authority on radiowaves and frequencies...in the US.