Weighing the Positives and Negatives in GMOs

Article Written by Joseph Lopez and Christine Nobleza
Illustration by Sophia Dumlao
Posted 20 June 2021

Genetically modified organisms (GMOs) are common in  the food market nowadays. In fact,  a study shows that genetic modification of crops increased  yields by 22% and farmer profits by 68% [1]. However, some people raised concerns about its safety as GMOs increased their reach.

First off, what exactly are GMOs? From the name itself, GMOs are organisms whose genome has been altered or modified in order to produce favorable traits [2]. These are done through recombinant DNA technology and reproductive cloning. 

One of the major  concerns against GMOs is its connection to glyphosate. Glyphosate is an ingredient in Monsanto’s herbicide, Roundup [3]. A study done last 2012 [4] concluded that there has been an increase in glyphosate-resistant weeds, causing  farmers to increase  the amount of herbicides applied to crops. In addition to this, the assessment done by the International Agency for Research on Cancer (IARC) [5] classified glyphosate as 2A or “possibly carcinogenic to humans.” Meaning, while it is already proven cancerous for animals, there is limited evidence of its carcinogenicity to humans [6]. Given this, more studies should be done in order to determine whether or not glyphosates are cancerous for humans and  to identify its other effects on our health.

Amidst this uncertainty, we can’t deny that GMOs have positive effects towards our environment. A report by Brookes and Barfoot found that GMOs have contributed to lowering levels of greenhouse gas emissions, with 2,456 million kg of carbon dioxide emissions reduced last 2018. This is because of the decreased fuel consumption from less frequent herbicide and pesticide applications, and the reduced energy use in soil cultivation [7]. The same report also found that the adoption of no-till farming systems for GMOs, a system where the soil is less disturbed compared to reduced tilling and traditional tiling systems, further diminished the greenhouse gas emissions of farming. Moreover, the report noted that GMOs lessen the need for new agricultural land as it usually increases yield, which will help the environment in the long run as undisturbed land such as forests reduce greenhouse gases.

However, GMOs might also have negative effects  on the environment. Outcrossing, the ‘transferring’ of genes from GMOs to conventional crops, may have undesired effects. Daniell’s study states that some of these concerns arose from the possibility of creating a ‘superweed’ that is resistant to herbicides because of a gene transfer [8]. Outcrossing may introduce undesired traits from GMOs to crops that undergo conventional breeding, or the breeding of two plants with the relevant characteristics without genetic modification [9], which may spell disaster once it  actually happens. 

As both conventional and GM seeds provide large yields for the masses to consume, strict measures to prevent outcrossing have been imposed. Conventional plant breeding urges that breeding should only occur between plants that are compatible with one another. This ultimately controls undesirable traits in prospective crops within a certain species as new traits gained from sexual reproduction are limited [10]. The same applies to GM crops, as these may crossbreed with other non-GM crops. On the other hand, handling GM crops call for good agricultural practice and strict control, which acts as the main route to admixture with other crops [11]. 

As one can deduct, outcrossing occurs quite easily, which urged for strict limitations of the growth of these crops. Furthermore, research was subsequently conducted in order to combat its negative impacts on agriculture. A study conducted by Van de Wiel and Lotz (2006) suggested that a distance of 250 m between conventional and GM crops is sufficient to prevent genes from the latter to transfer to neighboring crops [11]. However, in some cases, admixture does not occur even when certain species are not isolated from each other [11], this may be attributed to incompatibility in terms of reproduction. An alternative that is widely used to prevent outcrossing in GM crops is the utilization of Genetic Use Restriction Technologies (GURTs) or ‘terminator seed’ technology. Seeds from these GM plants would be unable to germinate, which is caused by activating genes in response to particular stimuli, and in turn, would not have viable offspring with wild species [12]. While they partly are beneficial, the usage of this technology impedes farmers financially. Since the seeds produced from this are not fertile, farmers are urged to buy a new batch of seeds yearly. It is deemed impractical, taking into account the traditional method of farming, which enables farmers to to save, reuse, and share seeds [13].

Furthermore, GM crops have been proved to be as nutritious and safe as their non-GM counterparts. In fact, some crops were specifically modified to have better nutritional value [14]. In many instances, GM crops have combated nutritional deficiencies; folate, a B-vitamin that is needed to perform necessary functions in the body [15], was increased by 150-fold in rice [16] using genetic engineering. This rice could potentially prevent a birth defect called “spina bifida”, which is caused by the lack of folate during pregnancy. In another instance, a Brazilian state company managed to increase folate by 15-fold in lettuce, which is sufficient for the daily nutritional needs of an adult [17]. 

Breeding of GM plants may also cause secondary metabolites, which are biochemical pathways that are antibiotic, antifungal, and antiviral; these subsequently protect plants from pathogens [18]. This enables the production of quality crops and the farmers’ increase of income. Moreover, GM crops are engineered to be more resistant to pesticides, which deem the consumption of these crops safe. While many pesticides are toxic, farmers have been switching from traditional pesticides to glyphosate, which are generally less harmful and less persistent compared to its traditional counterpart [19].

All in all, the perspective of many on GMOs, which are often hyperbolic assumptions of these as ‘harmful’ and ‘deadly’, are utterly incorrect. If there were no such breakthrough, many would have struggled and perished. As more concerns are rising in the agricultural and medical field, more innovative ways to counter this are called for, and over the time, perhaps GMOs would have aided many other fields, and not solely in the aforementioned areas. As science progresses, GMOs would have significantly improved, and the risks that these may possibly pose will be eliminated. Regardless, GMOs are proven to benefit the masses in the long run, which will inevitably enhance multiple aspects of every person’s life. 


1.      Klümper W, Qaim M. A Meta-Analysis of the Impacts of Genetically Modified Crops. Albertini  Emidio, editor. PLoS One. 2014 Nov 3;9(11):e111629.

2.      Fridovich-Keil JL, Diaz JM. Genetically modified organism [Internet]. Encyclopedia Britannica. 2021 [cited 2021 May 24]. Available from: http://www.britannica.com/science/genetically-modified-organism

3.      Cressey D. Widely used herbicide linked to cancer. Nature [Internet]. 2015 Mar 24; Available from: http://www.nature.com/articles/nature.2015.17181

4.      Benbrook CM. Impacts of genetically engineered crops on pesticide use in the U.S. — the first sixteen years. Environ Sci Eur. 2012 Dec 28;24(1):24. 

5.      Guyton KZ, Loomis D, Grosse Y, El Ghissassi F, Benbrahim-Tallaa L, Guha N, et al. Carcinogenicity of tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate. Lancet Oncol. 2015 May;16(5):490–1.

6.      International Agency for Research on Cancer. IARC Monographs on the Identification of Carcinogenic Hazards to Humans [Internet]. Lyon; 2019. Available from: https://monographs.iarc.who.int/wp-content/uploads/2019/07/Preamble-2019.pdf

7.      Brookes G, Barfoot P. GM crops: global socio-economic and environmental impacts 1996-2018 [Internet]. Dorchester; 2020. Available from: https://pgeconomics.co.uk/pdf/globalimpactfinalreportJuly2020.pdf

8.      Daniell H. Molecular strategies for gene containment in transgenic crops. Nat Biotechnol. 2002 Jun 1;20(6):581–6. 

9.       The Royal Society. How does GM differ from conventional plant breeding? [Internet]. 2016 [cited 2021 May 25]. Available from: https://royalsociety.org/topics-policy/projects/gm-plants/how-does-gm-differ-from-conventional-plant-breeding/

10.     Pocket K No. 13: Conventional Plant Breeding [Internet]. Conventional Plant Breeding | ISAAA.org. [cited 2021May26]. Available from: https://www.isaaa.org/resources/publications/pocketk/13/default.asp 

11.     Van De Wiel CCM, Lotz LAP. Outcrossing and coexistence of genetically modified with (genetically) unmodified crops: a case study of the situation in the Netherlands. NJAS – Wageningen J Life Sci. 2006;54(1):17–35. 

12.     What can be done to prevent cross breeding of GM crops? The Royal Society; [cited 2021May26]. Available from: https://royalsociety.org/topics-policy/projects/gm-plants/what-can-be-done-to-prevent-cross-breeding-of-gm-crops/ 

13.     How Terminator Seeds Threaten Sustainable Farming. The Borgen Project; 2019 [cited 2021May26]. Available from: https://borgenproject.org/terminator-seeds-threaten-sustainable-farming 

14.     GMOs and Your Health. Food and Drug Administration; [cited 2021May26]. Available from: https://www.fda.gov/media/135280/download 

15.     Ware M. [Internet]. Why is folate good for you? Medical News Today; 2018 [cited 2021May26]. Available from: https://www.medicalnewstoday.com/articles/287677 

16.    Blancquaert D, Van Daele J, Strobbe S, Kiekens F, Storozhenko S, De Steur H, et al. Improving folate (vitamin B9) stability in biofortified rice through metabolic engineering. Nat Biotechnol =. 2015 Oct 21;33(10):1076–8.

17.     Norero D. Unfairly demonized GMO crops can help fight malnutrition [Internet]. Alliance for Science. 2018 [cited 2021May26]. Available from: https://allianceforscience.cornell.edu/blog/2018/06/unfairly-demonized-gmo-crops-can-help-fight-malnutrition/ 

18.    Hussein RA, El-Anssary AA. Plants Secondary Metabolites: The Key Drivers of the Pharmacological Actions of Medicinal Plants [Internet]. IntechOpen. IntechOpen; 2018 [cited 2021May26]. Available from: https://www.intechopen.com/books/herbal-medicine/plants-secondary-metabolites-the-key-drivers-of-the-pharmacological-actions-of-medicinal-plants 

19.     Hsiao J. GMOs and Pesticides: Helpful or Harmful? [Internet]. Science in the News. 2019 [cited 2021May26]. Available from: https://sitn.hms.harvard.edu/flash/2015/gmos-and-pesticides/

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