The skin is the largest organ of the body and perhaps the most sensitive. The same principle that causes microwaves to cook food causes microwaves to burn, or essentially cook, skin. These burns go deep within the skin and are painful. Another sensitive organ is the eye, particularly the lens. The lens is sensitive to heat and the radiation of microwaves can damage it, causing cataracts, the clouding of the lens of the eye. These problems, while caused by microwave radiation, do not normally occur with microwave oven usage. The microwave oven is regulated by the Food and Drug Administration and while it can leak up to five milliwatts, it is not enough to cause major skin and eye damage.
The testes of the male reproductive system are very sensitive to heat and radiation as well. The production of sperm in the male testes is a very fragile process. Sperm are only produced in a temperature of close to 94 degrees, which is lower than core body temperature. When exposed to radiation, the temperature of the scrotal sac, where the testes are located, raises and causes temporary sterility. As in the case of skin and eyes, only high levels of radiation cause this problem. In pregnant women, microwave ovens were once believed to cause harm to the fetus. In 1993, the Oak Ridge Associated University panel concluded that microwaves produced by microwave ovens caused little, if any, damage to a developing fetus.
One of the main concerns with microwave ovens are pacemakers. Not long ago, pacemakers and microwave ovens conflicted with each other. Microwave radiation was once used to program pacemakers, so a person with a pacemaker had to be careful when near or using a microwave oven that leaked excessive radiation. Currently, pacemakers have become advanced and block the microwaves. Other concerns with microwave ovens are uneven heating in the food and extreme temperatures of cooked food.