A GMO, or genetically modified organism, is any plant, animal, or microbe whose DNA has been deliberately changed using laboratory techniques. Scientists alter the organism’s genetic code to give it traits it wouldn’t develop on its own, like resistance to insects or the ability to survive being sprayed with weed killer. If you live in the United States, you almost certainly eat foods made from GMO crops every day: more than 90 percent of all corn, soybeans, and cotton grown in the country come from genetically engineered seeds.
How GMOs Are Made
Traditional plant breeding works by crossing two related plants and hoping the offspring inherit the desired traits. Genetic engineering skips that slow process. Scientists identify a specific gene responsible for a useful trait, then insert it directly into the target organism’s DNA. That gene can come from the same species, a different species, or even a completely different kingdom of life, like transferring a gene from a bacterium into a plant.
The older method, called transgenic engineering, inserts foreign DNA somewhat randomly into the plant’s genome. A newer technique called CRISPR works differently. Instead of adding DNA from another species, CRISPR acts like molecular scissors that cut the organism’s existing DNA at a precise location. The cell then repairs itself, and that repair process can activate, deactivate, or subtly change an existing gene. Because CRISPR doesn’t necessarily introduce foreign DNA, many countries, including the United States, treat certain CRISPR-edited crops differently from traditional GMOs and exempt them from strict GMO regulations.
The Most Common GMO Crops
The vast majority of GMO crops fall into two categories: those engineered to tolerate herbicides and those engineered to resist insects. In 2025, 96 percent of U.S. soybean acres were planted with herbicide-tolerant varieties. About 92 percent of corn acres used herbicide-tolerant seeds, and 87 percent used insect-resistant varieties. For cotton, 93 percent of acres were herbicide-tolerant and 91 percent were insect-resistant. Herbicide-tolerant seeds are also widely used in alfalfa, canola, and sugar beet production.
Herbicide-tolerant crops let farmers spray weed killer on an entire field without harming the crop itself. Insect-resistant crops produce a protein that’s toxic to specific pests, so the plant essentially defends itself. These two traits dominate the market because they solve the two biggest problems in large-scale farming: weeds and bugs.
Beyond pest management, some GMOs are designed for nutritional goals. Golden rice is probably the most well-known example. Scientists inserted two genes involved in producing beta-carotene (the precursor to vitamin A) into the rice genome, giving the grain a yellow color and a nutrient it doesn’t normally contain. In parts of Asia where rice provides up to 80 percent of daily calories, golden rice could substantially reduce vitamin A deficiency, which causes blindness and weakened immunity in millions of children.
Effects on Pesticide Use
One of the biggest arguments for GMOs is that they reduce the need for chemical pesticides. The data over 24 years largely supports this. Between 1996 and 2020, the global adoption of insect-resistant and herbicide-tolerant crops reduced total pesticide use by about 749 million kilograms of active ingredient, a 7.2 percent drop. The environmental impact of that pesticide use fell by a larger 17.3 percent, because the chemicals that were eliminated tended to be the more harmful ones.
The biggest gains came from insect-resistant cotton, which cut insecticide use on cotton by roughly 30 percent worldwide, eliminating 339 million kilograms of insecticide. Insect-resistant corn reduced insecticide use by 41 percent. Herbicide-tolerant canola saw an 18 percent reduction in herbicide volume, while herbicide-tolerant soybeans showed only a marginal decrease of 0.1 percent, a reminder that the benefits vary by crop and region.
How GMO Foods Are Labeled
In the United States, foods containing GMO ingredients must carry a disclosure under the National Bioengineered Food Disclosure Standard. The standard defines bioengineered foods as those containing detectable genetic material that was modified through lab techniques and couldn’t have been created through conventional breeding. On packaging, you’ll see this disclosed through text (like “contains a bioengineered food ingredient”), a circular green symbol with the letters “BE,” a QR code, or a text-message number. Small manufacturers have additional options like phone numbers or web addresses.
The word “bioengineered” rather than “GMO” was a deliberate choice by regulators. If you’re scanning labels and don’t see the traditional “Non-GMO Project Verified” butterfly logo, look for the green BE symbol or the text disclosure instead.
How GMOs Are Regulated in the U.S.
Three federal agencies share oversight of GMO crops and foods, a system that’s been in place since 1986 under the Coordinated Framework for the Regulation of Biotechnology. The FDA ensures that GMO foods meet the same safety standards as all other foods, covering everything from production to processing to sale. The EPA regulates substances that protect GMO plants from insects and disease, including proteins the plants produce internally, along with any pesticides applied to them. The USDA’s Animal and Plant Health Inspection Service makes sure GMO plants won’t harm other plants or the broader agricultural system.
These agencies work together, and a single GMO crop often falls under the jurisdiction of all three before it reaches the market. Foods made from GMO ingredients go through the same safety evaluation process as their non-GMO counterparts. There is no separate, lower standard for GMO foods.
Why GMOs Are Controversial
The scientific consensus from major health organizations is that approved GMO foods are safe to eat. The controversy tends to center on broader concerns: corporate control over seed supplies, the environmental effects of monoculture farming, the development of herbicide-resistant weeds, and whether consumers have a right to know exactly what’s in their food regardless of safety assessments. Some people also object on principle to transferring genes across species, viewing it as fundamentally different from traditional breeding.
These debates are partly why labeling laws exist and why newer gene-editing techniques like CRISPR have created a regulatory gray area. If a crop’s DNA is changed without introducing foreign genes, some argue it’s no different from what could happen through natural mutation. Others maintain that any lab-based genetic alteration should be disclosed and regulated the same way. Different countries have landed on different answers, with Argentina deregulating most gene-edited crops while the European Union generally treats them as GMOs subject to strict oversight.