It's been said (many times) before, but bears repeating that pretty much all our foods have been genetically modified and not just by the modern technology of genetic engineering. Farmers and agricultural researchers have been selecting and cross-breeding plants for millenia to get rid of unwanted traits and emphasize ones they want. And sometimes the results are so far from the original that you'd have trouble matching the old to the new.
Check it out on the website of the Genetic Literacy Project, where the ancestors of corn, watermelon, eggplant, carrots, and that latest fad kale are displayed. But that's not all, of course. Peaches, tomatoes, tangerines, pluots, pink grapefruit and many others are the result of careful attention to the details of cross-breeding, as well as genetic changes (mutations) induced by newer procedures such as chemicals and radiation.
So we've been adding to the armamentarium that plant breeders can access for many years. Just think of that red grapefruit you've been enjoying for breakfast read about how it was produced by irradiating paler fruit here and consider whether this fruit can really be "all natural" or even organic. Is there something organic purveyors aren't telling us, especially since organic foods may not be irradiated to improve safety?
Now, of course, we've added genetic engineering the latest, most efficient means of improving our food crops. And what we hear are moans and groans about how these are unnatural procedures that interfere with our foods in dangerous ways. But it's never been shown that there's anything more dangerous about the most efficient means of genetic manipulation compared to more traditional ones.
We also are warned that genes that make crops pesticide-resistant will result in the weeds or other pests becoming resistant as well. That could happen as it does for non-engineered varieties. The agricultural community is constantly developing new chemicals to thwart plant and insect pests, and that is unlikely to change. What is valuable is that because of genetic engineering of pesticide resistance, we're using less of other pesticides. And isn't that a good thing?
For more accurate, scientifically sound information on the use of genetic engineering in agriculture, see the ACSH publication Food and You.