Perhaps you've seen it on your social media feed. Some Scandinavian, Norwegian, Slavic, etc girls did an experiment where they germinated some cress seeds "next to two [wifi] routers" and some not.
Astonishingly the seeds next to the router didn't fare so well.
Also remarkably, this experiment has never been repeated. Only the results rehashed slightly to make it more palatable for the writers current audience.
Snopes has it listed as unproven and calls into question the reliability of all the supporters.
I have my own take on this load of bollocks.
So, first off there is no reporting on the conditions of the experiment, so I can't tell how flawed it is, Let alone how to repeat it. There's only talk in generalities.
(I suspect the student set the test sample on top of the router and the heat from the running unit cooked the sprouts)
Let me cover what I know.
0. WiFi uses microwave frequency radiation on the order of 2.5gigahertz.
Microwaves are non ionizing, this means that there is not sufficient energy in any radio wave to affect the atomic makeup of any irradiated substance.
Microwaves are sufficiently low power that they cannot affect any molecular bonds that I am aware of. (Visible light, esp Blue, violet and ultraviolet light on the other hand is sufficiently energetic to affect molecular bonds etc)
By federal law, no WiFi access point designed for use indoors is allowed to emit more than a quarter Watt of power into the antenna. (2/3 of a Watt for outdoor units)
The intensity of "illumination" from an antenna is subject to the inverse square law, meaning that as distance is doubled, intensity is quartered.
From points 1 and 2, the only remaining energy form that could possibly affect life is in the form of heat. Microwaves can cause heating, and they do so quite well. The mechanism for this heating is actually friction.
Yes, friction, that very same thing that heats your hand when you rub them. The alternating radio waves cause the water molecules to flip back and forth much like a magnet causes a compass needle to swing around.
This motion causes them to rub on each other causing heat to be generated.
Extending point 3, i know from experience that 1/4 Watt is sufficient to heat about 1sq cm to between 50C and 100C (call it 70C temperature rise) this 70C is spread out over the surface of a sphere whose radius is the distance from the antenna. Even 1cm from the antenna we already have 1/12th of that.(6C) go out to 4cm (less than 2") and already there is enough surface area that the temperature rise is imperceptible except under extreme laboratory precision.