The biotechnology industry often claims that genetically engineered (GE/GMO) foods undergo some of the most rigorous safety testing in the world. What is rarely explained is that much of the international regulatory framework was built around two concepts developed in the early 1990s: Substantial Equivalence and Generally Recognised As Safe (GRAS).

• These concepts remain central to how many GMO foods are assessed today. It is also important to understand that these regulatory approaches did not emerge in isolation. During the late 1980s and early 1990s, biotechnology companies and food industry organisations actively participated in shaping regulatory policy in countries such as the United States. This resulted in regulations that were designed to encourage rapid commercialisation of genetically engineered products rather than requiring extensive long-term safety testing.
  
  

Substantial Equivalence

• Substantial Equivalence is the idea that if a genetically engineered crop looks chemically similar to its conventional counterpart, it can generally be treated as equally “safe”.
  

• Rather than requiring regulators to prove a GMO is completely safe through long-term animal feeding studies or human clinical research, developers compare selected characteristics of the GMO with an existing non-GMO counterpart.

These comparisons commonly include:

• Nutritional composition

• Protein, fat and carbohydrate levels

• Vitamins and minerals

• Known natural toxins

• Known allergens

• If these selected measurements fall within the normal range found in conventional crops, the GMO may be considered "substantially equivalent."

• Biotech proponents claim this is a reasonable, sensible scientific starting point because foods naturally vary between growing seasons and locations.

• However, substantial equivalence is a comparative concept, not a safety test. It does not directly investigate whether unintended genetic changes have occurred elsewhere in the genome, whether novel proteins behave differently over time, or whether subtle biological effects emerge after years of consumption. Demonstrating similarity in selected measurements is not the same as demonstrating long-term biological safety.
  
  

Generally Recognised As Safe (GRAS)

• The second concept commonly relied upon is GRAS, meaning Generally Recognised As Safe.
  

• Under this principle, substances with an established history of deemed “safe” use may not require extensive pre-market approval.
  

• When applied to biotechnology, many of the individual components used during genetic engineering – such as certain enzymes or proteins – may already be regarded as familiar or previously assessed. This creates an important distinction.
  

• While individual components may have previously been considered safe, the final genetically engineered organism is a new biological system.

  They argue that interactions between inserted genes, existing genes, cellular processes and environmental influences cannot always be predicted simply because each individual component has been studied before.
  

• For this reason, we must contend that evaluating the parts separately is not the same as evaluating the behaviour of the whole organism.
  
  

What Critics Say These Concepts Don't Prove

• GE/GMO scientists who question current GMO regulation are generally not arguing that every GMO is unsafe. Their concern is that the current regulatory framework was never designed to answer some of the most important scientific safety questions in the first place.

• That Substantial Equivalence and GRAS do not demonstrate:

• That unintended genetic changes have not occurred.

• That gene expression remains stable over generations.

• That new proteins cannot produce unexpected biological effects.

• That long-term, lifetime, or multi-generational health outcomes have been adequately investigated.

• That environmental interactions and ecosystem effects have been fully understood.

• These concepts are primarily regulatory screening tools, not comprehensive safety tests.
  

As Professor Philip James, former Chair of the European Commission's scientific committee responsible for GMO assessment, famously observed:

"Substantial Equivalence is a pseudo-scientific concept because it was created primarily to provide an excuse for not requiring biochemical or toxicological testing."

Whether one agrees with that assessment or not, it highlights an ongoing scientific debate that continues more than three decades after these regulatory principles were first adopted.

Not so “Safe and Precise”

• It is now well evidenced that supposedly “safe and precise” gene editing disrupts multiple gene functions in ways that persist through successive cell generations. These unnatural gene changes migrate through the environment into our soils, water, crops, and our native species, with no way to stop or retrieve them. Some of these unintended consequences from patenting life through genetic engineering include:

• Modified BT insecticide from GMO corn found in foetal cord blood and increasing antibiotic resistance and gut dysbiosis in humans.

• Reduced yields, increased pesticide use and weed resistance from GMO Roundup Ready soybeans

• Abortion and deformities in all experimental GE animals at NZ's Ruakura research station
  

Genetically modified foods are dangerous to human health

• A January 2022 study published in the Journal of Environmental Science Europe concluded, “Serious adverse events of GM consumption include mortality, tumour or cancer, significant low fertility, decreased learning and reaction abilities, and some organ abnormalities.”
  

• GMO crops have been associated with serious intestinal infections, allergies, premature births, kidney collapse, auto-immune disorders and intergenerational birth defects.
  

• Microbes, like bacteria, transfer genetic material between species, especially in the presence of environmental toxins. In genetically engineered bacteria, there have been thousands of unanticipated gene changes documented. Their gene function becomes unpredictable and no longer works as intended. These unpredictable traits get passed around the microbiomes — soil, water, air, plant, animal, and humans.
  

• Genetic modification of bacteria can be seen as a form of infection, similar to the bad effects of antibiotic resistance. Studies confirm that CRISPR gene editing creates thousands of unpredicted proteins and mutation reactions, with significant cancer tendencies that can be spread to unmodified species, like our food crops and our guts and skin. These effects can spread to us. These ‘off-target’ effects are not just a localised failure; they are a permanent alteration of the biological landscape.
  

“Only lab containment will keep rampant unknown GMO contamination out of all foods and crops.” Professor Jack Heinemann, University of Canterbury, Oct. 2025

The profound risks of GMO release are frequently downplayed by regulatory bodies beholden to industrial biotech interests. We are currently playing a high-stakes game with the fundamental building blocks of life, and the architects of this technology have no intention of accepting accountability when (not if) their containment gene modifications inevitably fail.