I would recommend becoming informed about the GMO issue. Dr. Joseph Mercola has a great downloadable article that explains the issue well with detailed look at the history of it. The first GMO Patent was given in 1980, then approved in 1982 by the Federal Government.
Genetically Modified Food are altered in a laboratory. In 1996, Monsanto biotech company designed the food item to be glyphosate resistant. Now, the food can tolerate the herbicide and the weeds can be killed. So far the top things that are now primarily GMO are alfalfa, apples, canola, sugar beets, potato, soy, and corn.
Aside from promoting mono-culture framing, it can be at least partly blamed for killing bees and butterflies. The bad part in my opinion is the ruined health of humans too. Gut health is compromised, causing harm with our own microbiome (gut flora). A build up of toxins too is harmful. health affects are published to be: autism, allergies, cancer, Parkinson's, Crohn's, Infertility, MS, obesity, depression and many more.
Things are not consistently labeled. In fact many companies have paid good money not to label the food. So there are others that have tried to do the opposite, ironically there are companies that are involved in labeling organic and non-GMO. You can look for that in the store.
Here is the link for the entire article or come to the office, we have a copy in our waiting room. www.mercola.com/ebook/gmo-foods.aspx