Epidemiology studies investigating cell phone use patterns with human cancer risk have produced inconsistent results. Some studies enrolled people who already had tumors with suspected links to RF radiation, such as gliomas, acoustic neuromas and salivary gland tumors. Researchers compared the self-reported cell phone use habits of the cancer patients with those of other people who did not have the same diseases. Other studies enrolled people while they were still healthy, and then followed them over time to see if new cancer diagnoses tracked with how they used cell phones. All the epidemiology studies, however, have troubling limitations, including that enrolled subjects often do not report their cell phone use habits accurately on questionnaires.

Pong’s claims for its case have stood up to the scrutiny of Wired magazine and the Better Business Bureau (Advertising Self-Regulation Council 2012; Ganapati 2009). In tests conducted by Cetecom, a cell phone radiation certification lab, and observed by a reporter from Wired magazine, an iPhone 3G tested without a case had a maximum SAR of 1.18 W/kg when held at the ear. The same phone tested with a Pong case had a maximum SAR of 0.42 W/kg (Ganapati 2009).  

In 2011, researchers at the National Institutes of Health showed that low-level radiation from an activated cell phone held close to a human head could change the way certain brain cells functioned, even without raising body temperature. The study did not prove that the effect on brain cells was dangerous, only that radiation from cell phones could have a direct effect on human tissue.

When you talk, your voice is transmitted from the antenna as radio frequency radiation (RFR) between 800 MHz and 2,200 MHz. A range equal to the middle of microwave frequency and 20% to 80% of the radiation emitted is deposited in the user's head. The microwave radiation is absorbed and penetrates the area around the head, some reaching an inch, to an inch and a half into the brain. Exposure to this microwave RFR has shown to have serious health consequences. Laboratory studies have shown that radiation from cell phones expose the user to a wide range of health problems including: 

There’s no question that portable phones and computers offer many conveniences and have made our lives easier in countless ways. For many people this convenience outweighs the worry of EMFs. My hope is that by becoming aware of the sources and dangers of cell phone radiation and EMFs, you’ll take steps to minimize exposure for both you and your family.
Generally, the Ministry of Health adopts the instructions of most international entities, recommending to follow the “precautionary principle” regarding mobile phone use. The instructions of the Ministry take into account the technological need of the population in Israel, along with the measure of precaution necessary according to the recent scientific information in order to balance between the population’s needs and the preservation of its health.
Homeopathic remedies, credit cards and passports with chips, and electronic equipment can all be compromised by exposure to electromagnetic fields. The EMP Can™ is a great air-tight way to store these items and protect them from outside EMF influences including low grade EMP. Shields both radiofrequency and magnetic fields by 95% or more. All metal construction, nice wide mouth and quick-close latch keep contents secure.
In the studies, the researchers looked at a whole slew of health outcomes (like offspring survival, bodyweight changes, and body temperature changes), but importantly, they also looked at brain tumors, including gliomas. They exposed the animals to radio frequency radiation for up to nine hours a day over two years, and then examined more than 40 tissues in each animal. And they had a control group that wasn’t exposed to radiation for comparison.
Mobile or cell phones are now a days an integral part of modern telecommunications in every individual life. In many countries, over half of the population use mobile phones and the mobile phone market is growing rapidly. Saudi Arabia rank first among the countries of the gulf region with highest proportion of mobile users, a study conducted by United Nations Conference on Trade and Development (UNCTAD). In gulf countries, Oman ranked second, followed by Kuwait and the UAE. As billions of people use mobile phones globally, a small increase in the incidence of adverse effects on health could have major public health implications on long term basis. Besides the number of cell phone calls per day, the length of each call and the amount of time people use cell phones are important factors which enhance the health related risk. (1)
The only consistently recognized biological effect of radiofrequency radiation in humans is heating. The ability of microwave ovens to heat food is one example of this effect of radiofrequency radiation. Radiofrequency exposure from cell phone use does cause heating to the area of the body where a cell phone or other device is held (e.g., the ear and head). However, it is not sufficient to measurably increase body temperature. There are no other clearly established effects on the human body from radiofrequency radiation.