All the hype around whether or not cell phones cause cancer could be linked back to the World Health Organization's 2011 conclusion that the radiation emitted by cellphones could be "possibly carcinogenic to humans." Reading that conclusion makes it easy to jump to the conclusion that cell phones are cancer-causing culprits, but really, this classification was based on admittedly limited evidence and essentially puts cell phones in the same danger zone as coffee and pickled vegetables. Since 2011 there have been multiple experiments done and research conducted about a connection between cell phone usage and the increase in cancer risk, but results have been mixed at best with no concrete causal link. In the end, researchers at the National Cancer Institute have concluded that ultimately new research needs to be done before we'll have a full answer.
When thinking about the radiation and cancer connection, remember that there are two kinds of radiation to compare: "non-ionizing electromagnetic radiation" (think microwaves) and "ionizing radiation" (think X-rays). Cell phones emit the non-ionizing kind of radiation, and it turns out that's a very good thing. Currently there is a study known as COSMOS being conducted in the UK that began back in 2010 and is following 290,000 cell phone users over the course of 20-30 years. These kinds of long-term experiments will hopefully fill in gaps of knowledge about the impact of cell phone radiation beyond what's already been learned from short-term experiments. If you can't wait another 20 or 30 years for the results from COSMOS and are concerned about the potential risks, try to minimize your overall use, text rather than call people, and keep your distance from your phone as much as possible--a headset helps.
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