 Do mobile phones cause cancer? That's a question billions of people would like to know, and that's why we have the World Health Organization's IARC, the recognized authority on what is and is not carcinogenic. There are five categories. There are the Group 1 carcinogens. Those we know, with the highest level of certainty, do cause cancer in human beings. Then there are things that probably cause cancer, possibly cause cancer, were not sure, or probably don't cause cancer. In May 2011, 30 scientists from 14 countries met at the IARC to assess the carcinogenicity of the radiation emitted from cell phones and concluded that given the limited amount of available evidence, cell phones are a possible human carcinogen. So not a definite human carcinogen, not a Group 1 carcinogen known to be cancer-causing like plutonium or processed meat, not a probable carcinogen like DDT or Monsanto's Roundup Pesticide or some regular meat, but a possible carcinogen down around something like preserved vegetables like kimchi. Now that was more than five years ago. This continues to mount, with the latest to 2017 systematic reviews showing, between a 33% increase odds of brain tumors, with long-term use, to 46% higher odds of tumors on the phone side of your head. And that's including the industry-funded studies that have been accused of being biased and flawed, underestimating the risk, as opposed to independent studies free from financial conditioning. How's that for euphemism? And so some scientists are pushing to have the IARC bump cell phones up to probable carcinogens or even all the way up into Group 1, at least for brain cancer and acoustic neuromas, which is a type of inner ear tumor. But the IARC classification for cell phones currently remains that possible carcinogen. So what does that mean? What do we do with that information? Well, given the uncertainty, we could follow the precautionary principle and use simple personal measures to reduce our exposure, like not putting the phone directly up to our head all the time. That's the main concern about cell phones, holding it to our head. Whereas there's no evidence of finger cancer risk, so text away. This is considered particularly important for children. Other potential personal recommendations waiting a moment before putting your cell phone to your ear if you don't have a headset. And don't fall for those anti-radiation gizmos that may make things worse, actually, by forcing the phone to boost the signal. Not all agree with this precautionary approach, however. Employees at two cell phone industry trade organizations emphasize that there are many aspects of human activity that are not totally without adverse health effects, and so we should just accept the risk as being worth it. For example, air travel and hot showers? What, like we might scald ourselves or something? In any case, we shouldn't put out any recommendations. This should be left up to the judgment of the parents on a personal basis for their own children. If we put out some kind of guidelines or something, it might make people nervous, and we all know anxiety can have deleterious health consequences itself, so basically the cell phone industry cares so much about your health that it doesn't want you worrying your pretty little head. But that is something openly discussed in the risk analysis literature. Yeah, from a public health perspective, it might be reasonable to provide cell phone users with voluntary, precautionary recommendations for their cell phone handling in order to enable them to make informed decisions. But you know, what if the public can't handle the truth? We don't want to freak people out, there's still scientific uncertainty. We don't want to foster inappropriate fears. For example, brain cancer is rare to begin with. We only have like a 1 in 15,000 chance of getting a brain tumor every year. So even if cell phones doubles your risk, that would only take you up to 1 in 7,500 chance. You may be more likely to get killed by a cell phone in the hands of some distracted driver than by cancer. So whether health authorities want to inform the general public about precautionary possibilities really remains more of a political decision.