I know someone, who has some, shall we say, possbily not credible beliefs.
But one really stumped me, and it's the concept that localised EMF (electro magnetic fields) can damage your cells, he said something to do with calcium. It was all very tin foil hat.

He thinks that WiFi on your phones, WiFi routers and Bluetooth can cause health problems.

I wanted to know, is there any credible scientific fact for this? Or maybe even against, i just can't seem to find much information on it at all.

Thanks in advance