Having had a cell phone since age 11, I have gotten warnings from various friends that the more I use a cell phone, the more likely I will get brain cancer from the radiation. I figured it might be legitimate, so I started primarily using speaker phone in my tween years. Then I realized that my fear had no real basis other than some hullabaloo from some paranoid friends. Now, 8 years into the future, there have been a great number of research experiments looking into if these relatively essential devices are causing one of the worst diseases of our lifetime.
The American Cancer Society has an entire page on its website dedicated to cell phones and their presumed linkage to cancer, which is where I started my research. The mechanism established as the connection between cell phone usage and brain cancer is the radiofrequency waves, which fall on the electromagnetic energy spectrum between FM radio waves and microwaves (cancer.org). The main concern arises from how close the antenna, which is where the waves stem from the strongest, gets to your head and how often you make phone calls. It was proposed that, because phones have become so heavily used since the 1990s, that this form of radiation from the phones would cause brain tumors to develop after heavy usage of cell phones (cancer.org). The American Cancer Society states that the specific absorption rate (SAR) is what measures the amount of radiofrequency wave energy that the body absorbs; this rate varies across all cell phones (cancer.org).
It is explained on American Cancer Society webpage that lab studies have been done in which animals are exposed to these radiofrequency waves, but that there is an issue with the ability to truly generalize these results to humans. In studies done with humans, the amount of variations in cell phone use are difficult to facilitate, especially since creating a control group would mean having to find people who would limit their cell phone use or have to abstain completely (cancer.org).
Now, in 2016, multiple studies have been done to help build support in either proving or disproving this hypothesis that heavy phone usage increases the risk of brain cancer. Most studies are conflicting in their findings and so a consensus is yet to be made. For example, I found this 2011 article by John Timmer noting a 15-year-long study in Denmark that little to no correlation was found between cell phone use and rates of gliomas and meningiomas (types of brain cancers). It states, though, that the study is ongoing.
In an article written by Timothy J. Moynihan for the Mayo Clinic he notes that a study that was done with 420,000 participants over the span of 20 years found no evidence of cell phones causing brain tumors. He explains that cell phones cannot yet be labeled a carcinogen (Moynihan). In drawing a parallel to the research development that cigarette smoking causes cancer, Moynihan discusses how since this is a new technology being studied for causation of cancer, it will take many more years to be able to sufficiently be able to look for causation (Moynihan).
The bottom line, as stated in the explanatory American Cancer Society webpage and Moynihan’s article, is that due to the weighing of costs and benefits, if you would like to further limit the possibility that your phone will cause cancer, there are a number of things you can do. Some ideas include only using a headset/earbuds to talk on the phone, exclusively texting, or using a phone with a low specific absorption rate (SAR) value. There is a relatively thorough list of popular phones and their SAR values found on the linked webpage.