The bulk of scientific evidence says that cellphone radiation doesn’t harm humans, according to the Food and Drug Administration: our cellphones are much more likely to kill us when we glance down at them while driving. But people are bad at judging risk. And the word “radiation” combined with the fact that we can’t see or control the invisible forces emanating from our cellphones becomes a perfect recipe for fear.
Most of these early studies did not find an increase in the risk for developing tumors among mobile phone users. The main problem characterizing these studies stems from the fact that the development of cancer (in particular brain tumors) takes a very long time (at least 10-20 years and up to 40 years or more), while mobile phone technology is relatively new (as aforesaid, popular use began only in the mid-90s). Hence, these studies could not demonstrate risk even if such existed.
Some products (http://www.safecell.net/reports01.html for example) are tested using a piece of shielding material in a laboratory test jig. These tests legitimately show the amount of radiation which penetrates the shield, but results will be very different when compared to putting a small amount of the same shield on a large transmitter like a cellphone. Remember, the entire phone radiates. Placing a small amount of shielding, even if it is an effective shielding material, only shields that small area at best. Think about this analogy: no light will penetrate a penny as it is a very effective light shield, but it is silly to think that holding a penny up to the sun will put you in darkness.
The papers found that, in male rats, there was “clear evidence” that exposure to cell phone radiation increased risk for a rare type of malignant tumor called schwannoma in the connective tissues that surround nerves in the heart (they found “equivocal” evidence for the same thing in female rats). They also found “some evidence” that the radiation caused malignant glioma—a type of brain cancer affecting glial cells—in the male rats.
Exposure to ionizing radiation, such as from x-rays, is known to increase the risk of cancer. However, although many studies have examined the potential health effects of non-ionizing radiation from radar, microwave ovens, cell phones, and other sources, there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans (2).