So basically genetically engineered/modified foods are foods that have been bred with genes from different organisms. This process is called recombinant DNA technology. Farmers use this technology in order to create insecticide and herbicide resistant crops or to enhance other nutritional characteristics of the plant. There is much controversy surrounding the issue.
The benefits include improved taste and quality, reduced maturation time, stress tolerance, resistence to disease, pests and herbicides, conservation of soil, water and energy and even waste management. There is also an increased food security for growing populations.
The negative outcomes include allergens, transfer of antibiotic resistance markers, unintended transfer through cross-pollination, unkown effects, tampering with nature, no regulations on labeling, domination of world food production by a few companies, and the advances may be skewed to interests of rich nations.
hmmm...interesting huh. :P