The idea that cell phones, routers, wireless heart rate monitors, alarm clocks or pretty much any other electronic device will give you cancer is one of the most persistent fears around. The good news is, it’s also one of the most baseless.
Cancer is the result of a problem in your DNA. These problems can originate from a natural mutation, wherein the body's DNA replication machinery makes a mistake, or from an outside influence on the body. One of these outside influences is radiation. Radiation is energy moving in a wave, and like any wave (think sound or water waves) it has wavelength and frequency. The longer the wavelength, the longer it takes for the wave of energy to make 1 full up-down-up cycle. So a wave with a large wavelength will have a low frequency, and visa-versa. It is only electromagnetic waves with high enough energy, that is frequency, that can penetrate our bodies and harm us. So high energy = high frequency = low wavelength = bad. When electromagnetic energy reaches a target, it transfers some of its energy to it, which can result in knocking electrons out of atoms. This loss of electrons can lead to breaks in chemical bonds, like the ones that your DNA has. We call radiation with enough energy to knock out electrons ionizing radiation, and it’s only this kind of radiation that poses a threat to humans. The frequency at which non-ionizing radiation becomes ionizing is in the ultraviolet range, or somewhere below wavelengths of 10^-7 m.
Cell phones use radio waves to communicate with cell towers, and these waves have wavelengths of approximately 10-1000 m, which are much too large to be ionizing. WiFi actually operates at quite precise frequencies, either 2.4 GHz or 5 GHz, which correspond to wavelengths of either 12 cm or 6 cm. In fact, if you look at your router controls, you’ll probably see a setting to switch between the 2 radio waves. Practically, the 2.4 GHz frequency will perform slower than the 5 GHz, but for a larger distance. At my house, we set up both, so that we can work inside or out.
The moral of the story is, cell phones, radios, and WiFi are not causing cancer, they are physically unable. But if you still aren’t convinced, click here to watch a video in which they review the studies done on low-frequency electromagnetic radiation exposure.
(Spoiler, they found no risks).