Like humans, all organisms have genetic material. When scientists alter genetic material, or DNA, it's called genetic modification (GM). Historically, crops have been genetically tweaked to be herbicide-resistant or insect-resistant, and scientists are stacking traits to address both pest and weed problems.

Market watchers estimate that upwards of 70% of processed foods in your local supermarket contain genetically modified ingredients.

Here’s a look at the major genetically engineered foods that have made it onto the dinner plate.

Corn - Number 1 crop in the U.S. Nearly 88% of corn is genetically modified. In addition to being added to innumerable processed foods, genetically modified corn is a staple of animal feed.

Soy - 93% of soy is genetically modified. Soy is a staple of processed foods under various names including hydrogenated oils, lecithin, emulsifiers, and proteins.

Cottonseed - 94% of cotton grown in the U.S. is genetically modified. Cottonseeds are culled from cotton, and then used for vegetable oil, margarine or frying foods, such as potato chips.

Alfalfa - Farmers feed alfalfa to dairy cows, the source of milk, butter, yogurt, meat and so much more. Alfalfa is the fourth largest crop grown in the U.S., behind corn, soybeans, and wheat.

Papaya - 75% of the Hawaiian papaya crop is genetically modified.

Canola - 90% of the U.S. canola crop is genetically modified. Canola oil is used in cooking, as well as biofuels.

Sugar Beets - 54% of sugar sold in America comes from sugar beets. Genetically modified sugar beets account for 90% of the crop.

Statistics and information provided by the US Department of Agriculture and the Huffington Post.