It has become one of the perennial topics of debate in the 21st century - are the mobile devices we increasingly use to work, socialise and entertain ourselves online, making us physically ill?
After all, our use of gadgets that rely on wireless technology is unprecedented in history - surely all the radio waves produced by those billions of Wi-Fi routers, smartphones and tablets are having some affects on us?
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Actually, the scientific answer is no, they are not. The radiation these devices put out cannot physically harm us. To put it in technical terms, there is no biological mechanism whereby it can cause things like brain tumours, fertility problems or headaches.