[Mollocephalus]

As it was pointed out, GMOs are not harmful per se. If you think about it, most of the food we eat was selected during the centuries. Wheat was selected to be high and prolific, tomatoes used to be tiny yellow berries at the times of roman empire and it was only recently that the red tomatoes, both big and small, emerged. Even cattle and dogs were selected from their wild counterparts.

The real, big problem lies in the kind of modification you make. Due to the high consumption of wheat based products (not to mention dairy products), in our age we have diseases that weren't so prominent a hundred years ago, or didn't exist at all! The modifications you can make via artificial selection are limited by the time it takes and the chance of the right dna string going exactly where you want to, while with genetic engineering you can modify things in a much easier way. That is, you can modify things even in the most unnatural way. Since there is a huge market and a lot of interests behind these things, i am not surprised there is bias over the effect of certain GMOs. To make some plants un-attackable by parasites, the chemical balance of said plant has to be modified, therefore what you eat can change pretty significantly from the organic version of it; if there's something potentially harmful in it, it's usually long-term health problems, which are more difficult to investigate to find their underlying causes.

Last but not least, genetically modified plants (like some animals, a blatant example is salmon fish) can end up being much more aggressive when they grow in the wild, suffocating or replacing the natural version of the same plant (or animal).

In my opinion, it's a good idea to consume local organic products as much as possible in order to preserve yourself, the environment, and your local economy.

@kommisar: you make a pretty naive argument. taste is only marginally related to the nutritional value/healthyness of a food.