GMOs – Top 3 Pros and Cons

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Test hybrid corn sprouts being grown in a nursery near Kihei, Hawaii.
Source: Matthew Thayer/The Maui News
Associated Press, “Hawaii Counties Can’t Regulate GMOs and Pesticides According to New Ruling,”, Nov. 16, 2016

Selective breeding techniques have been used to alter the genetic makeup of plants for thousands of years. More recently, genetic engineering has allowed for DNA from one species to be inserted into a different species to create genetically modified organisms (GMOs). [1][2]

Examples of GMOs include apples that don’t turn brown and disease-resistant papayas. [3] [4] At least 26 countries, including the United States, grow genetically modified crops, while 19 of 28 European Union nations have partially or fully banned GMOs. [5] [6] Food and ingredients from genetically engineered plants have been in our food supply since the 1990s. [7]

In the United States, the health and environmental safety standards for GM crops are regulated by the Environmental Protection Agency (EPA), the Food and Drug Administration (FDA), and the US Department of Agriculture (USDA). [44] Since 1985, the USDA has approved over 17,000 different GM crops for field trials, including varieties of corn, soybean, potato, tomato, wheat, rapeseed (canola) and rice, with various genetic modifications such as herbicide tolerance, insect resistance, flavor or nutrition enhancement, drought resistance, and fungal resistance. [45]

The National Bioengineered Food Disclosure Standard established mandatory national standards for labeling foods with genetically engineered ingredients in the United States. The Standard was implemented on Jan. 1, 2020 and compliance becomes mandatory on Jan. 1, 2022. [46]

Is genetic modification a helpful application of technology that makes plants resistant to pests and disease while improving nutritional value, or an unnatural tinkering with our food supply that lacks sufficient regulation and oversight?

Should Genetically Modified Organisms (GMOs) Be Grown?

Pro 1

Genetically modified (GM) crops have been proven safe through testing and use, and can even increase the safety of common foods.

Over the past 30 years of lab testing and 15 years of field research, there has not been a single health risk associated with GMO consumption. [8] Martina Newell-McGoughlin, PhD, Director of the University of California Systemwide Biotechnology Research and Education Program, said that “GMOs are more thoroughly tested than any product produced in the history of agriculture.” [8]

Over 2,000 global studies have affirmed the safety of GM crops. [10] Trillions of meals containing GMO ingredients have been eaten by humans over the past few decades, with zero verified cases of illness related to the food being genetically altered. [11]

GM crops can be engineered to reduce natural allergens and toxins, making them safer and healthier. Molecular biologist Hortense Dodo, PhD, genetically engineered a hypoallergenic peanut by suppressing the protein that can lead to a deadly reaction in people with peanut allergies. [12]

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Pro 2

GMO crops lower the price of food and increase nutritional content, helping to alleviate world hunger.

The World Food Programme, a humanitarian organization, estimates that 821 million people in the world are chronically undernourished, and one in nine people face hunger. [13] Population growth, climate change, over-farming, and water shortages all contribute to food scarcity. [14] GMOs can help address those problems with genetic engineering to improve crop yields and help farmers grow food in drought regions or on depleted soil, thereby lowering food prices and feeding more people. [15] [16]

David Zilberman, PhD, Professor of Agricultural and Resource Economics at UC Berkeley, said that GMO crops have “raised the output of corn, cotton and soy by 20 to 30 percent, allowing some people to survive who would not have without it. If it were more widely adopted around the world, the price [of food] would go lower, and fewer people would die of hunger.” [17]

To combat Vitamin A deficiency, the main cause of childhood blindness in developing countries, researchers developed a GMO ‘Golden Rice’ that produces high levels of beta-carotene. [18] [19] A report by Australia and New Zealand’s food safety regulator found that Golden Rice “is considered to be as safe for human consumption as food derived from conventional rice.” [20]

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Pro 3

Growing GMO crops leads to environmental benefits such as reduced pesticide use, less water waste, and lower carbon emissions.

The two main types of GMO crops in use today are engineered to either produce their own pesticides or to be herbicide-tolerant. [21] More than 80% of corn grown in the US is GMO Bt corn, which produces its own Bacillus thuringiensis insecticide. [22] This has significantly reduced the need for spraying insecticides over corn fields, and dozens of studies have shown there are no environmental or health concerns with Bt corn. [23]

Drought-tolerant varieties of GMO corn have been shown to reduce transpiration (evaporation of water off plants) by up to 17.5%, meaning less water waste. [24]

Herbicide-tolerant (Ht) GMO soy crops have reduced the need to till the soil to remove weeds. [26] Tilling is a process that involves breaking up the soil, which brings carbon to the surface. When that carbon mixes with oxygen in the atmosphere, it becomes carbon dioxide and contributes to global warming. [25] Reduced tilling preserves topsoil, reduces soil erosion and water runoff (keeping fertilizers out of the water supply), and lowers carbon emissions. [27] [28][29] The decreased use of fuel and tilling as a result of growing GM crops can lower greenhouse gas emissions as much as removing 12 million cars from the roads each year. [30]

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Con 1

Genetically modified (GM) crops have not been proven safe for human consumption through human clinical trials.

Genetically modified ingredients are in 70-80% of food eaten in the United States, even though there haven’t been any long term clinical trials on humans to determine whether GMO foods are safe. [31] [32]

Scientists still don’t know what the long-term effects of significant GMO consumption could be. Robert Gould, MD, a pathologist at the UC San Francisco School of Medicine, said, “the contention that GMOs pose no risks to human health can’t be supported by studies that have measured a time frame that is too short to determine the effects of exposure over a lifetime.” [33]

According to the Center for Food Safety, a US-based nonprofit organization, “Each genetic insertion creates the added possibility that formerly nontoxic elements in the food could become toxic.” The group says that resistance to antibiotics, cancer, and suppressed immune function are among potential risks of genetic modification using viral DNA. [34]

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Con 2

Tinkering with the genetic makeup of plants may result in changes to the food supply that introduce toxins or trigger allergic reactions.

An article in Food Science and Human Welfare said, “Three major health risks potentially associated with GM foods are: toxicity, allergenicity and genetic hazards.” The authors raised concerns that the GMO process could disrupt a plant’s genetic integrity, with the potential to activate toxins or change metabolic toxin levels in a ripple effect beyond detection. [35]

A joint commission of the World Health Organization (WHO) and the Food and Agriculture Organization of the UN (FAO) identified two potential unintended effects of genetic modification of food sources: higher levels of allergens in a host plant that contains known allergenic properties, and new proteins created by the gene insertion that could cause allergic reactions. [36]

The insertion of a gene to modify a plant can cause problems in the resulting food. After StarLink corn was genetically altered to be insect-resistant, there were several reported cases of allergic reactions in consumers. The reactions ranged from abdominal pain and diarrhea to skin rashes to life-threatening issues. [37]

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Con 3

Certain GM crops harm the environment through the increased use of toxic herbicides and pesticides.

Since herbicide-resistant GM crop varieties were developed in 1996, an “epidemic of super-weeds” has developed resistance to the herbicides that GM crops were designed to tolerate. [38] Those weeds are choking crops on over 60 million acres of US croplands, and the solution being presented to farmers is to use more herbicides. [39] This has led to a tenfold increase in the use of the weed killer Roundup, which is made by Monsanto, the largest GMO seed producer. [33][38]

The increased use of the weed killer glyphosate can harm pollinating insects and potentially create health risks for humans ingesting traces of herbicides used on GM crops. [41] When glyphosate is used near rivers, local wildlife is impacted. The use of Roundup, whose active ingredient is glyphosate, can lead to higher mortality rates among amphibians. [42] Scientists blame Roundup for a 90% decrease in the US monarch butterfly population. [38]

A report from the Canadian Biotechnology Action Network found that “GM crops have also had a number of impacts on biodiversity. Herbicide-tolerant crops reduce weed diversity in and around fields, which in turn reduces habitat and food for other important species.” [43]

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Did You Know?

  1. An estimated 94% of all soybean and 92% of all corn grown in the US is genetically modified and around 75% of all processed foods in the US contain GMO ingredients. [47] [48]
  2. At least two-thirds of all GM corn and half of all GM soy grown in the US are converted into animal feed. [49]
  3. In 1994, the “FLAVR SAVR” tomato became the first genetically modified food to be approved for public consumption by the US Food and Drug Administration (FDA). [50] The tomato was genetically modified to increase its firmness and extend its shelf life. [51]
  4. There are currently 10 genetically modified (GM) crops in production in the United States (also referred to as genetically engineered, or GE, crops), including corn, soybeans, and cotton. [52]
  5. 49% of US adults believe that eating GMO foods are “worse” for one’s health, 44% say they are “neither better nor worse,” and 5% believe they are better, according to a 2018 Pew Research Center report. [9]
Click for an Encyclopaedia Britannica video answering the top questions about GMOs

Discussion Questions

  1. Should GMOs be grown and used in foods? Why or why not?

2. Should food labels include whether GMO plants have been included in the products? Why or why not?

3. What other ways can world hunger be alleviated if not via GMOs? Explain your answers.

Take Action

1. Consider Megan L. Norris’ answer to the question “Will GMOs Hurt My Body?

2. Discover “Science and History of GMOs and Other Food Modification Processes” according to the Food and Drug Administration (FDA).

3. Explore Farm Aid’s argument to change the GMO status quo.

4. Consider how you felt about the issue before reading this article. After reading the pros and cons on this topic, has your thinking changed? If so, how? List two to three ways. If your thoughts have not changed, list two to three ways your better understanding of the “other side of the issue” now helps you better argue your position.

5. Push for the position and policies you support by writing US national senators and representatives.


1.Theresa Phillips, "Genetically Modified Organisms (GMOs): Transgenic Crops and Recombinant DNA Technology,", 2008
2.Chelsea Powell and Ana Maurer, "How to Make a GMO,", Aug. 9, 2015
3.Chase Purdy, "The First Non-Browning, Genetically Modified Apple Is Shipping to US Groceries,", Nov. 7, 2017
4.David Johnson and Siobhan O’Connor, "These Charts Show Every Genetically Modified Food People Already Eat in the US,", Apr. 30, 2015
5.Genetic Literacy Project, "Where Are GMO Crops and Animals Approved and Banned?," (accessed July 22, 2019)
6.European Commission, "Several European Countries Move to Rule out GMOs," (accessed June 25, 2019)
7.US Food and Drug Administration (FDA), "Questions & Answers on Food from Genetically Engineered Plants,", Jan. 4, 2018
8.Best Food Facts, "GMOs and Human Health,", Apr. 18, 2018
9.Pew Research Center, "Public Perspectives on Food Risks,", Nov. 19, 2018
10.Alan McHughen, "GMO Safety and Regulations,", Dec. 16, 2014
11.David H. Freedman, "The Truth about Genetically Modified Food,", Sep. 1, 2013
12.Becky Ferreira, "This Food Scientist Wants to Save Lives with a Hypoallergenic Peanut,", Jan. 26, 2018
13.World Food Proramme (WFP), "2019 - The State of Food Security and Nutrition in the World (Sofi): Safeguarding Against Economic Slowdowns and Downturns,", July 15, 2019
14.World Economic Forum, "Food Security and Why It Matters,", Jan. 18. 2016
15.David S. Levin, "Op-Ed: GMOs Could Be the Solution to Africa’s Food Shortages,", July 26, 2017
16.Jennifer Ackerman, "Food: How Altered?," (accessed July 22, 2019)
17.David H. Freedman, "The Truth about Genetically Modified Food,", Sep. 1, 2013
18.Genetic Literacy Project, "What Is Nutritionally Enhanced Golden Rice and Why Is It Controversial?," (accessed July 22, 2019)
19.World Health Organization (WHO), "Global Prevalence of Vitamin a Deficiency,", 1995
20.Food Standards, "Approval Report – Application A1138,", Dec. 20, 2017
21.Genetic Literacy Project, "Which Genetically Engineered Crops and Animals Are Approved in the US?," (accessed July 22, 2019)
22.United States Department of Agriculture Economic Research Service, "Recent Trends in GE Adoption,", July 16, 2018
23.Michael S. Koach, Janson M. Ward, Steven L. Levine, James A. Baum, et al., "The Food and Environmental Safety of BT Crops,", Apr. 29, 2015
24.Krishna S. Nemali et al., "Physiological Responses Related to Increased Grain Yield under Drought in the First Biotechnology-Derived Drought-Tolerant Maize," Plant, Cell & Environment, Sep. 11, 2014
25.Danielle Prieur, "Could No-Till Farming Reverse Climate Change?,", Aug. 4, 2016
26.International Service for the Acquisition of Agri-Biotec Applications (ISAAA), "Resources Publications Pocket K Herbicide Tolerance Technology: Glyphosate and Glufosinate Pocket K No. 10: Herbicide Tolerance Technology: Glyphosate and Glufosinate,", Oct. 2018
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28.National Academies of Sciences, Engineering, and Medicine, "The Impact of Genetically Engineered Crops on Farm Sustainability in the United States,", 2010
29.Jon Entine and Rebecca Randall, "GMO Sustainability Advantage? Glyphosate Spurs No-Till Farming, Preserving Soil Carbon,", May 5, 2017
30.Graham Brookes and Peter Barfoot, "Environmental Impacts of Genetically Modified (Gm) Crop Use 1996–2015: Impacts on Pesticide Use and Carbon Emissions,", May 2, 2017
31.Grocery Manufacturers Association, "Grocery Manufacturers Association Position on GMOs,", Sep. 23, 2013
32.Genetic Literacy Project, "Why Are There No Long-Term GMO Safety Studies or Studies on Humans?," (accessed June 24, 2019)
33.Consumer Reports, "GMO Foods: What You Need to Know Why Is There so Much Fuss over Genetically Modified Ingredients? This Will Help You Sift Through the Facts.,", Feb. 26, 2015
34.Center For Food Safety, "GE Food & Your Health," (accessed July 23, 2019)
35.Chen Zhang, Robert Wohlueter, and Han Zang, "Genetically Modified Foods: A Critical Review of Their Promise and Problems,", Sep. 2016
36.Food and Agriculture Organization of the United Nations and World Health Organization, "Evaluation of Allergenicity of Genetically Modified Foods,", Jan. 2001
37.CBS News, "Life-Threatening Food?,", May 17, 2001
38.Consumer Reports, "GMO Foods: What You Need to Know Why Is There so Much Fuss over Genetically Modified Ingredients? This Will Help You Sift Through the Facts.,", Feb. 26, 2015
39.Patricia Callahan, "EPA Tosses Aside Safety Data, Says Dow Pesticide for GMOs Won't Harm People,", Dec. 8, 2015
40.Consumer Reports, "GMO Foods: What You Need to Know Why Is There so Much Fuss over Genetically Modified Ingredients? This Will Help You Sift Through the Facts.,", Feb. 26, 2015
41.Garden Organic, "GMOs - Environmental Concerns," (accessed July 23, 2019)
42.Jessica Neves, Adam D'Agostino, and Alicia Zolondick, "Environmental Impact of GMOs,", Apr. 20, 2016
43.Canadian Biotechnology Action Network (CBAN), "Are GMO Crops Better for the Environment?,", May 2015
44.US Department of Agriculture, "Regulation of Biotech Plants," (accessed June 23, 2019)
45.Jorge Fernandez-Cornejo, Seth Weshsler, Mike Livingston, and Lorrie Mitchell, "Genetically Engineered Crops in the United States,", Feb. 2014
46.United States Department of Agriculture, "BE Disclosure," (accessed June 23, 2019)
47.United States Department of Agriculture, "Adoption of Genetically Engineered Crops in the U.S.," (accessed July 23, 2019)
48.Center for Food Safety, "About Genetically Engineered Foods," (accessed June 23, 2019)
49.GMO Answers, "GMOs and Livestock," (accessed June 23, 2019)
50.Chicago Tribune, "FDA OKs Calgene's Flavr Savr Tomato, a 1st for Whole Biotech Food,", May 18, 1984
51.G. Bruening, and JM Lyons, "The Case of the Flavr Savr Tomato,", July 1, 2000
52David Johnson and Siobhan O'Connor, "Health Diet/Nutrition These Charts Show Every Genetically Modified Food People Already Eat in the U.S.,", Apr. 30, 2015