http://cryptome.org/fda102099.htm
 
A few animal studies, however, have suggested that low levels of RF could
accelerate the development of cancer in laboratory animals. In one
study, mice genetically altered to be predisposed to developing one
type of cancer developed more than twice as many such cancers when
they were exposed to RF energy compared to controls. There is much
uncertainty among scientists about whether results obtained from
animal studies apply to the use of mobile phones. First, it is
uncertain how to apply the results obtained in rats and mice to
humans. Second, many of the studies that showed increased tumor
development used animals that had already been treated with
cancer-causing chemicals, and other studies exposed the animals to the
RF virtually continuously--up to 22 hours per day.
 
So Look who's talking, Muth? No one talks on a cell phone for 22 hours straight! According to the FDA, there is no evidence saying cell phones cause cancer.