0) Cell phone radiation is strictly regulated in the U.S. to a maximum Specific Absorption Rate of 1.6 Watts per kilogram. Some of the newer phones have a measured SAR of as low as 0.194 Watts per kilogram.
1) Cell phones emit non-ionizing radiation
2) The inverse-square law insures that the effective radiation is so minimal as to be non-consequential
3) Bone and water are quite opaque to microwave radiation, and you have, hopefully, a good thickness of skull and Cerebro-Spinal Fluid between your cell phone and your brain further attenuating the signal to near-nothingness
4) There are no peer reviewed studies showing any causal link between cell phone use and increased risks of cancer
5) There are a couple of decent studies that do show an increased risk for certain extremely rare types of cancer (such as acoustic glioma) but even a doubling of such tiny numbers means that the risks are still minuscule
6) Any concerns about the sheer number of cell phones in use increasing cancer risks is bogus because of 2)
See:
http://en.wikipedia.org/wiki/Specific_absorption_ratehttp://reviews.cnet.com/4520-6602_7-5020356-1.html?tag=rb_content;rb_mtxhttp://en.wikipedia.org/wiki/Inverse_square_lawhttp://www.nytimes.com/2008/06/03/health/03well.htmlThe risks of breathing in second hand smoke, especially in confined spaces such as cars, are so much greater than the chances of developing cancer from even very high cell phone usage as to make any comparison laughable. That being said, I wouldn't be in favor of addressing this issue through the law. We know from drug and alcohol prohibition that criminalizing drug/alcohol usage doesn't really accomplish anything except to make criminals out of people. Education is the best tool we have here.