A little over 20 years ago, the U.S. government approved the first genetically modified crops for wide scale planting. Since then, Genetically Modified Organisms (GMOs) or Genetically Engineered crops (GEs) have become big business—and controversial. That’s one reason the National Academies of Sciences, Engineering and Medicine recently released a 388-page report assessing the pros and cons of GMOs and the risks they pose to human health and the environment.
Though the GMO and GE are often used interchangeably, they aren't the same. All creatures naturally undergo genetic modification overtime, but "genetically engineered" specifically refers to using modern biotechnology to alter genes.
The GE era began in earnest in 1995 with the introduction of Bt corn which includes genes from the bacteria Bacillus thuringiensis that produce a biopesticide lethal to some insect larvae. Now, there are 12 commercially-grown GE crops including cotton, corn, soybeans and sugar beets, Elizabeth Weise reports for USA Today. GE variety of these crops are especially popular, making up over 90 percent of each sold in United States. About 12 percent of all crops in the world are now GE.
But debate still rages over their safety and environmental impacts, with critics calling for strict product labeling. So 50 scientists and agriculture experts examined over 900 studies to compile what they say is the most up to date information on GE crops. Here are the five most important things to know.
GE Crops Are Safe to Eat
Though GE crops have been in food supplies for years, there has been no greater increases in problems like cancer, allergies or stomach problems in GE-consuming popuations, like the U.S., compared to relatively GE-free populations, like much of Europe. In addition, no effects of GE foods have been found in animal toxicity tests or health of GE-consuming livestock.
The study acknowledges, however, that the effects of GE crops could be complex and there may be subtle health differences that develop over time not previously identified, urging continued monitoring.
GE Doesn’t Improve Crop Yields
Proponents of GE farming have insisted that the varieties lead to increased crop yields, but the study found that except in a few cases this wasn’t the case. The exception, according to the report, is when insect and pest pressures are high. But overall, yearly increases in crop yield haven't exceeded growth before GEs came on the scene.
“The expectation from some of the proponents was that we need genetic engineering to feed the world and were going to use genetic engineering to make that increase in yield go up faster,” Fred Gould, a professor of agriculture at North Carolina State University and chair of the report committee tells Dan Charles at NPR. “We saw no evidence of that.”
Genetically Engineered Labeling Is Getting Even Hazier
For the last two decades there has been a relatively clear understanding of GEs—any organism that has received a gene or DNA from another organism. But that definition is quickly aging as new molecular tools are blurring the lines. New techniques like CRISPR gene editing may allow researchers to directly edit a plant’s DNA, while other tools could allow researchers to identify plants with unique mutations to use for more traditional breeding.
Instead of just looking at GMO crops, the report urges a new regulatory system to look at the safety of all new crops.
We Still Haven’t Figured Out the Butterfly Situation
One of the first big controversies surrounding GE crops began in the late 1990s when researchers worried that pollen from Bt corn was killing the larvae of monarch butterflies. But a series of studies put those concerns to rest by 2002.
Even so, the recent decline in monarch numbers at over-wintering sites in Mexico has raised concerns that widespread use of Roundup on crops reduced wild milkweed abundance, which monarchs use for food and egg laying. Some recent studies show that monarchs have started laying more eggs to adjust to the lower milkweed abundance, and declines may be related to weather, parasites or disease at the insects' over-wintering grounds. But the report says more study is needed to decide if reduction in milkweed is the primary problem.
The Debate Is Bigger Than Science
The debate surrounding GE crops is not just about whether they are safe or harmful, it's about who should use GE crops, how they should be made available and what the public should know. "Not all issues can be answered by science alone,” the report states.
“I sincerely hope that this study expands the conversation beyond technological determinism and the tired, old, two-sides-to-every-argument approach to discussing GE crops," Leland Glenna, a member of the report committee tells IFLScience. "It is common for GE crops to be portrayed either as solutions to social and economic problems or as causes of them.”
But the debate on GE crops is far more complicated than this, Glenna notes. "The report makes it very clear that assessing the experiences of and prospects for GE crops is about more than merely evaluating technical risks. Legal, economic, social, cultural and individual factors are also relevant.”