All electromagnetic radiation is formed of a continually oscillating electric field vector (oscillating between +Amplitude and -Amplitude) with a magnetic field vector doing the same thing, but perpendicular to it.

Microwaves (and radio) are produced by oscillating electric charges. When the charges are moving one way it's a +ve current and -ve if the other way. Microwaves are microwaves, there only differences are the power and frequency.

In terms of what this guy's saying, microwaves only heat up food because they make polar molecules (like water) vibrate. They don't do anything to the internal workings of the molecule (unless it gets hot enough to break up).

Simply put, microwaves don't have enough energy to cause 'chemical' changes in atoms. This is how UV, XRay and Gamma causes cancer, by altering the chemistry of DNA molecules in your cells. There's no way microwaves can do that. It's possible that there may be another, more complicated mechanism that could be activated by them, but I doubt it.

Oh, I was going to do a quick explanation of sources (I am about to do this in class :D)

Radio - caused by large oscillation of electric charges - any A.C. running along a wire 10+cm long will give out a bit of radio wave

Microwave - same cause as radio, but shorter wavelength. I always use a microwave oven as a baseline. There's about 2-3 waves fitting into an oven.

IR - Now we get a bit smaller, thermal infrared is caused by oscillation of molecules - anything warm (above absolute zero) will be giving off IR

Visible - (as well as Near-IR) is caused by atomic vibrations or high energy heating (bulbs, THE SUN)

UV - now we start getting into energy transitions in the atom - things getting hit by other EM radiation can cause this and make stuff give off UV. Interestingly, UV paint/ink doesn't "glow" in UV, it absorbs UV light and re-emits in in a lower frequency, otherwise we wouldn't be able to see it.

X-Rays - you can give off x-rays with REALLY hot stuff. In fact, old X-ray sources would be similar to a souped up CRT. Also, pulling sellotape fast off the rolls gives off a few x-rays :)

Gamma - can only be cause by stuff going on in the nucleus - radioactive materials, nuclear bombs, fission, fusion, or nuclei that have been excited someway.

That's fair enough. I guess it's just not for me.

I need two hands to count the number of computers I own and make use of. I use at least 4 of those on a day to day basis.