The recent study  about cell phones causing cancer in rats should be taken with a grain of salt when making the connection to humans . In particular, the rats in the study were exposed to radiation power densities of 0, 1.5, 3, or 6 W/kg (see p 7 in ref. 4 below). This would be equivalent of the 100 kg human getting up to 600 Watts — basically getting microwaved. As discussed earlier, cell phones are hundreds of times weaker.
Pong Research also makes cases for the iPad and its technology is arguably better suited for that. Why? Because serving as a stand to prop up your iPad or tablet, it means you don’t really need to hold it. That’s an ideal setup because higher amounts of radiation are going out the back, versus the front of the screen which you are touching with your fingers and palms.
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.
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).