(Intro)

A lot of people worry that their cell phone will give them cancer, which isn't all that surprising. I mean, you're holding a device that emits radiation right next to your brain! Terrible idea, right? Well, no.

Some kinds of radiation can damage DNA, which can then lead to cancer. But your cell phone doesn't give off that kind of radiation. And even if there was a way that cell phone radiation could hurt you, studies have shown that it doesn't.

Cell phones communicate with cell towers using a form of radiation known as radio frequency, or RF, radiation. The word "radiation" is just in there because it's a type of energy on the electromagnetic spectrum. The spectrum goes from low energy at one end to high energy at the other. Radio and microwaves are near the low end. Gamma rays and X-rays are near the high end. It can help to think of electromagnetic radiation as a wave, with a certain frequency based on its energy. The higher the energy, the higher the frequency.

When an electromagnetic wave hits an atom, it transfers some energy to that atom. When the wave has a high enough frequency, meaning it has a lot of energy, it can transfer enough energy to the atom to knock out an electron. Electromagnetic energy that can knock out electrons is called ionizing radiation, and it can break chemical bonds in your cells and damage your DNA. In other words, it's the cancer-causing kind.

When electromagnetic energy doesn't have a high enough frequency to break chemical bonds, it's called non-ionizing radiation. If non-ionizing radiation hits an atom, it isn't going to be able to knock out an electron. So it can't damage cells, and it can’t cause cancer. It doesn't matter how strong the beam of radiation is. Its ability to knock out electrons only depends on its frequency, which isn't affected by the intensity of the radiation. It's like your microwave. No matter how powerful it is, it's never going to start emitting infrared radiation which would be the next level up in frequency.

The cutoff between ionizing and non-ionizing radiation is somewhere in the ultraviolet range. That's above visible light in frequency, and way above the radio waves that cell phones use. Which is why, based on what we know about physics and biology, there's nothing cell phones do that can give you cancer.

However, doctors and scientists do take the potential health risks of mobile phones seriously, and a lot of studies have been done to see if there's a link between cell phones and cancer. Sometimes, these studies do find what sounds like a relationship between cell phones and cancer, at least, at first. For example, one study of a million women in the UK found what seemed to be a weak link to a tumor called an acoustic neuroma, a benign tumor in the nerve that leads from the ear to the brain. More frequent cell phone use was correlated with a higher risk of getting this tumor. But the study followed the subjects for seven years. If there actually was a connection between this tumor and cell phone use, you'd expect more people to develop the tumor as they were exposed to more radiation over time. But the numbers didn't go up. Based on that, and the fact that other large studies haven't found the same connection, the authors of the study concluded it was just a statistical fluke.

Another large study from the World Health Organization found an increase in glioma among the 10% most frequent cell phone users. It's a type of nerve cell tumor that's responsible for most cases of malignant brain cancer. However, there were problems with that study: They collected the data by having people report their own cell phone use, and people tend to remember incorrectly. Plus, people who used their cell phones infrequently had a lower risk of glioma than people who didn't use them at all. If cell phone radiation was causing the tumors, that wouldn't make any sense.

And the vast majority of other studies have found no evidence that cell phones can cause tumors. There's also the fact that if cell phones were causing some kinds of cancer, we'd be seeing the rates of those cancers go up. I mean, something like 5 billion people use cell phones, and they've been commercially available since the mid-1980s. That’s long enough for cancer to start showing up, even if it takes a few decades to develop.

Which is exactly what happened after cigarettes started being mass-produced. Lung cancer used to be pretty rare, but when smoking cigarettes started to become more popular, lung cancer rates went way up. There just isn't any sign of this when it comes to cell phones. Both the number of people who get brain cancer, and the number of people who die from it, is holding steady even as cell phone use skyrockets. So go ahead and make as many phone calls as you want.

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(Outro)

Hank: ...we return to some pre-industrial revolution pastoral life style, cancer wouldn't just vanish. Lot's of things that cause cancer have been around for as long as the human race, or longer...