Note: Although it is true that cell phones emit low frequency magnetic fields that can be measured in milliGauss, they also emit high frequency microwave radiation which is what all the concern (and publicity) is about, and which the products below are designed to shield. Many clients have contacted us seeking a shield for BOTH magnetic fields and microwaves for their phone. Such a shield does not currently exist. To reduce your exposure to BOTH types of radiation, use an airtube headset and keep the phone itself at a distance.
Use the speaker mode on the phone or a hands-free device such as a corded or cordless earpiece. This moves the antenna away from your head, which decreases the amount of RF waves that reach the head. Corded earpieces emit virtually no RF waves (although the phone itself still emits small amounts of RF waves that can reach parts of the body if close enough, such as on the waist or in a pocket). Bluetooth® earpieces have an SAR value of around 0.001 watts/kg (less than one thousandth the SAR limit for cell phones as set by the FDA and FCC).
What the study showed: Self-reported cell phone use was not associated with an increased risk of glioma, meningioma, or non-central nervous system tumors. Although the original published findings reported an association with an increased risk of acoustic neuroma (14), this association disappeared after additional years of follow-up of the cohort (15).

The study also found that about 5 to 7 percent of the male rats exposed to the highest level of radiation developed certain heart tumors, called malignant schwannomas, compared to none in the control group. Malignant schwannomas are similar to acoustic neuromas, benign tumors that can develop in people, in the nerve that connects the ear to the brain.

That brings us back to the main question here: Do cellphones cause tumors? We chose to focus this story on cancer risk, since it seems like the most common health concern people have about cellphones. But before we get to the answers, we need to take another (brief) detour to explain how this science has been done with human subjects. To do that, we need to zoom in on a nerdy subject: research methods.

Dr. Carlo, wrote a  Medical Alert ten years ago. He cautioned people with EMF sensitivity against relying upon widely-available EMR Protection Products to prevent the effects of EMF exposure. He noted that EMF sensitive individuals were reporting the opposite effect: people found their symptoms and/or sensitivity worsened. Specifically, severe “symptom relapses.” Dr. Carlo noted:

“We see either no change or very small increases in incidence in some tumor types,” Quinn Ostrom, the Baylor College of Medicine researcher who has been analyzing these cancer trends, explained. “I would be inclined to say this isn’t as much of an increase as you might expect if cellphones were causative [of brain tumors] due to the very sharp way use of these devices has gone up over the last 20 years.”

Since speaking with Samet, further details came out from a large study that beamed high levels of phone radiation at rats and mice. While there remain quirks in the findings, the latest evidence still doesn’t find a link between phone radiation and cancer. In response, the FDA said, “Taken together, all of this research ... [has] given us the confidence that the current safety limits for cell phone radiation remain acceptable for protecting the public health.”
The only sure way is to stop using a cell phone. Most people however would prefer to play safe by simply reducing their exposure to radio frequency radiation. Bluetooth devices emit only 10% of the radiation of a cell phone. A hands-free set enables the user to keep the phone away from the head but usually leaves the phone near some other part of the body. It is safe to say that in the event that radio frequency radiation causes damage, you would like to protect other parts of your body. Therefore the only way to reduce your risk is to reduce the radio frequency radiation your body absorbs. SAR Shield reduces radio frequency radiation by up to 89%. 
 I purchased two different color cases and I was surprised when I received it because the inner case was different than described in some of the reviews. But when I looked at the Amazon listing, I didn’t realize that the case has been updated and I’m pleasantly surprised. The inner case is a soft, flexible plastic that doesn’t seem like it would break at all. I borrowed an EMF reader from a friend and the case works as described. I’m very happy with the cases and I’m glad that I purchased one for my boyfriend too! I definitely recommend this case!
In subsequent analyses of Interphone data, investigators addressed issues of risk according to specific location of the tumor and estimated exposures. One analysis of data from seven of the countries in the Interphone study found no relationship between brain tumor location and regions of the brain that were exposed to the highest level of radiofrequency radiation from cell phones (9). However, another study, using data from five of the countries, reported suggestions of an increased risk of glioma and, to a lesser extent, of meningioma developing in areas of the brain experiencing the highest exposure (10).