Though with the empirical usefulness of most machines the myths associated with them died out, the legion of microwave myths still refuse to fade. Only a few years back, an email circulated which cited an uncontrolled experiment of the writer's granddaughter's science project, observing effect of microwaved water on plants, and extrapolating it to humans.
Needless to say that once the experiment was repeated under controlled conditions it showed that the plants thrived just as well on water that has been microwaved and cooled. This is an example of the baseless cases made against microwaves, supported by a 'microwave militia', as a blogger termed them, who will support anything anti-establishment. These grand claims include that microwaved food shots the DNA, brain, hormones, nutrition, blood etc. The most often quoted authority on this matter is Dr Hans Hertel, who concluded that microwaved food causes cancer and alters blood, by isolating himself and seven peers and taking nothing but milk and vegetables prepared in different ways for two months. This equates nothing more than scientific gibberish.
Micro waves are electromagnetic waves and heat food by causing motion of certain polar molecules, commonly water, not making the water in anyway 'poisonous'. The temperature never goes over 100 degrees centigrade or 212 degrees Fahrenheit, so carcinogenic substances such as char never form. Most importantly, microwaves are not ionising radiation, which cancer causing rays are.
All cooking processes change food chemically and the microwave is not perfect either, though not in any way worse. While it may preserve the nutrients in spinach, it reduces active Vitamin B12 and so on, the varying with the time food is cooked for and the quantity of water added. Radiation emanating from the microwave is highly regulated by the FDA and is much lower than the figure known to cause damage to our bodies. Even so, if microwaves were really part of some hushed up corporate conspiracy, there would have been some people manifesting symptoms over the more than 50-year-long history of their use.
Another incident that the aforementioned email alluded to was that of a Canadian nurse who transfused blood warmed in a microwave resulteing in death of the patient. This is due to the non-uniform and accelerated heating of blood which causes cells to breakdown, and not due to DNA damage as asserted. At any rate, as long as it is employed for cooking purposes only, one should not have to worry. The microwave like all electronics comes with a manual. There are certain techniques to its use. And burns, well, are not unique to it, for everything hot can singe. So don't rush to the store if you are out of matchboxes and want a cup of tea.