All I have read is pseudo scientific stuff coming from the homeopathic and naturopath crowd. They claim the molecules get screwed up by the radiation, then upsetting your body. The microwave scare is as old as the microwave ovens. Did you know when electric ovens came on the market, there were people that claimed their roasts tasted "electric"?
When trains were introduced, there were people that believed the speed would make you ill. This never ends - people fear new things.
Think of this - if microwaves were detrimental to your health, life expectancy in the US would have seriously declined in the 70s and 80s when microwaves were introduced to practically every household in the nation.
Cheers,
George