Should You Be Concerned About GMOs?

Scientist examining genetically modified plants in greenhouse
Zomi/Getty Images

There are many identified risk factors for cancer, and obesity is one of them. Another potential risk factor appears to be emerging: the intake of certain herbicides used on common genetically modified crops in the United States.

What Are GMOs?

GMO stands for “genetically modified organism,” and this particular kind of biotechnology (genetic engineering) has been applied to common food crops, such as corn and soybeans.

In fact, the vast majority of corn and soybeans grown in the U.S. are now genetically engineered.

The stated purpose of genetically engineered crops has included: increasing crop yields, producing foods that are resistant to mold, creating crops that can thrive on salt water irrigation, and allowing for the growth of agricultural plants that are resistant to herbicides, so that weeds may be easily killed without affecting desired plants.

Science-Backed Concerns About GMOs

A number of scientists, public health experts, and physicians have raised concerns in recent years regarding GMOs. Some of these concerns have been regarding the potential for GMOs to produce new and unanticipated allergens that will lead to new food allergies. Other concerns have been about potential nutritional alterations in the quality of the food we eat.

Some of the most alarming scientific evidence that raises concerns about GMOs has to do with the kinds of herbicides that are used on GMO crops.

GMOs and Herbicides

Corn and soybeans that were genetically engineered to withstand the herbicide glyphosate (Roundup) were first made available in the mid-1990s, and these GMO crops now comprise more than 90 percent of the corn and soybeans planted in the U.S.

The big problem with glyphosate is that the International Agency for Research on Cancer (IARC) has stated that it is a “probable human carcinogen”—and this is the herbicide most commonly and widely used on GMO crops.

This means that the most commonly used herbicide on most of the corn and soybeans sold and consumed in the U.S.—not to mention other genetically modified foods that are increasing in number—is likely to cause cancer.

Even more concerning is that the Environmental Protection Agency (EPA) made a decision in 2014 to approve a new combination herbicide, Enlist Duo, which contains both glyphosate and 2.4-D—the latter of which was a component of Agent Orange (the toxic herbicide and defoliant used in the Vietnam War that has been recognized by the Department of Veterans Affairs to be associated with a number of cancers and other diseases).

Labeling of GMOs

Although 64 other countries require GMO labeling to identify to consumers which foods are or contain GMOs, the U.S. Food and Drug Administration currently does not.

A number of countries and regions, ranging from countries in the European Union to Saudi Arabia to Thailand and the Philippines, have banned some or all GMOs.

In the United States, a number of non-governmental organizations, such as the Non-GMO Project, have added their voices to those of public health experts raising a number of serious concerns about GMOs.


Adoption of genetically engineered crops in the U.S. Washington, DC: Department of Agriculture, Economic Research Service. Accessed online at on August 23, 2015.

Guyton KZ, Loomis D, Grosse Y, et al. Carcinogenicity of tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate. Lancet Oncol. 2015;16:490-491.

Landrigan PJ, Benbrook C. GMOs, herbicides, and public health. N Engl J Med. 2015;373:693-695.

Continue Reading