Williams concedes that he is among a tiny minority of biologists raising sharp questions about the safety of GM crops. But he says this is only because the field of plant molecular biology is protecting its interests. Funding, much of it from the companies that sell GM seeds, heavily favors researchers who are exploring ways to further the use of genetic modification in agriculture. He says that biologists who point out health or other risks associated with GM crops—who merely report or defend experimental findings that imply there may be risks—find themselves the focus of vicious attacks on their credibility, which leads scientists who see problems with GM foods to keep quiet.
Whether Williams is right or wrong, one thing is undeniable: despite overwhelming evidence that GM crops are safe to eat, the debate over their use continues to rage, and in some parts of the world, it is growing ever louder. Skeptics would argue that this contentiousness is a good thing—that we cannot be too cautious when tinkering with the genetic basis of the world's food supply.
To researchers such as Goldberg, however, the persistence of fears about GM foods is nothing short of exasperating. So who is right: advocates of GM or critics?
When we look carefully at the evidence for both sides and weigh the risks and benefits, we find a surprisingly clear path out of this dilemma. The bulk of the science on GM safety points in one direction. Take it from David Zilberman, a U. Berkeley agricultural and environmental economist and one of the few researchers considered credible by both agricultural chemical companies and their critics. He argues that the benefits of GM crops greatly outweigh the health risks, which so far remain theoretical.
It has 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.
In the future, Zilberman says, those advantages will become all the more significant. The United Nations Food and Agriculture Organization estimates that the world will have to grow 70 percent more food by just to keep up with population growth. Climate change will make much of the world's arable land more difficult to farm. GM crops, Zilberman says, could produce higher yields, grow in dry and salty land, withstand high and low temperatures, and tolerate insects, disease and herbicides.
Despite such promise, much of the world has been busy banning, restricting and otherwise shunning GM foods. Nearly all the corn and soybeans grown in the U. Ten E. Approval of a few new GM corn strains has been proposed there, but so far it has been repeatedly and soundly voted down. Throughout Asia, including in India and China, governments have yet to approve most GM crops, including an insect-resistant rice that produces higher yields with less pesticide.
In Africa, where millions go hungry, several nations have refused to import GM foods in spite of their lower costs the result of higher yields and a reduced need for water and pesticides. Kenya has banned them altogether amid widespread malnutrition.
No country has definite plans to grow Golden Rice, a crop engineered to deliver more vitamin A than spinach rice normally has no vitamin A , even though vitamin A deficiency causes more than one million deaths annually and half a million cases of irreversible blindness in the developing world.
Globally, only a tenth of the world's cropland includes GM plants. Four countries—the U. Other Latin American countries are pushing away from the plants.
And even in the U. In the U. The fear fueling all this activity has a long history. The public has been worried about the safety of GM foods since scientists at the University of Washington developed the first genetically modified tobacco plants in the s.
In the mids, when the first GM crops reached the market, Greenpeace, the Sierra Club, Ralph Nader, Prince Charles and a number of celebrity chefs took highly visible stands against them. Consumers in Europe became particularly alarmed: a survey conducted in , for example, found that 69 percent of the Austrian public saw serious risks in GM foods, compared with only 14 percent of Americans.
In Europe, skepticism about GM foods has long been bundled with other concerns, such as a resentment of American agribusiness. Whatever it is based on, however, the European attitude reverberates across the world, influencing policy in countries where GM crops could have tremendous benefits.
The human race has been selectively breeding crops, thus altering plants' genomes, for millennia. Ordinary wheat has long been strictly a human-engineered plant; it could not exist outside of farms, because its seeds do not scatter.
The practice has inspired little objection from scientists or the public and has caused no known health problems. The difference is that selective breeding or mutagenic techniques tend to result in large swaths of genes being swapped or altered. GM technology, in contrast, enables scientists to insert into a plant's genome a single gene or a few of them from another species of plant or even from a bacterium, virus or animal.
Supporters argue that this precision makes the technology much less likely to produce surprises. Most plant molecular biologists also say that in the highly unlikely case that an unexpected health threat emerged from a new GM plant, scientists would quickly identify and eliminate it.
And although it might seem creepy to add virus DNA to a plant, doing so is, in fact, no big deal, proponents say. Viruses have been inserting their DNA into the genomes of crops, as well as humans and all other organisms, for millions of years. They often deliver the genes of other species while they are at it, which is why our own genome is loaded with genetic sequences that originated in viruses and nonhuman species.
People who are more personally concerned about the issue of GM foods are especially worried that such foods will lead to health and environmental problems for society. In contrast, majorities of those who are less engaged with this issue say environmental and health problems stemming from GM foods are not too or not at all likely. These expectations of risks for society from GM foods are in keeping with the wide differences among these groups in their views of the health risks associated with eating GM foods.
Men and women have somewhat different expectations for GM foods. Men are more optimistic, while women are more pessimistic about the likely impact of GM foods on society. These modest differences in expectations by gender are in keeping with other studies. There are modest generational differences in expected effects from GM foods.
Adults ages 65 and older are less pessimistic than their younger counterparts about the likely effects of GM foods for society; more adults ages 65 and older say harm to the environment or to public health from GM foods is not at all or not too likely to occur. But younger adults, especially those ages 18 to 29, are more likely to think that GMOs will result in more affordably priced foods. Those with high science knowledge are more optimistic in their expectations that GM foods will bring benefits to society.
Education, which is closely linked with levels of science knowledge, shows a similar pattern. Postgraduate degree-holders are more inclined to say GM foods are very likely to increase the global food supply and to lead to more affordably priced food than those with less education. Public views of scientists and their understanding about the health risks and benefits of GM foods are mixed and, often, skeptical.
Most Americans perceive considerable disagreement among scientific experts about whether or not GM foods are safe to eat. While most people trust scientists more than they trust each of several other groups to give full and accurate information about the health effects of GM foods, only a minority of the public says they have a lot of trust in scientists to do this.
At the same time, most Americans say that scientists should have a major role in policy decisions about GM foods, but so, too, should small farm owners and the general public. Fewer Americans say that food industry leaders should play a major role at the policy-making table. But views of scientists connected with GM foods are often similar among those who with deep personal concern about the issue of GM foods and those with less concern. Differences are more pronounced between these groups when it comes to views of industry influence on scientific research findings and trust in food industry leaders to give full and accurate information about the health effects of GM foods.
In other respects, people with deeper concern about this issue vary only modestly from other Americans in their views of scientists and the scientific research on GM foods.
A recent report from the National Academies of Sciences, Engineering and Medicine concluded there was no persuasive evidence that genetically engineered crops have caused health or environmental problems.
For example, those who view GM foods as worse for health are especially inclined to say that there is little agreement among scientists about the safety of GM foods.
Past Pew Research Center studies have found a similar pattern when it comes to perceptions of scientific consensus and beliefs about climate change as well as beliefs about evolution. Across all levels of concern about this issue, few see broad consensus among scientists that GM foods are safe to eat.
Similarly, people who have heard or read a lot about GM foods are far more likely than those who have heard or read nothing about this issue to see consensus among scientists that GM foods are safe. About one-third of Americans say scientists understand the risks and benefits of eating GM foods not too well or not at all well. Those who perceive broad scientific consensus on the safety of GM foods are more likely to think scientists understand this topic.
By comparison, fewer people who do not care at all or not too much about this issue give scientists high marks for their understanding of the health effects of GM foods. Although, roughly similar shares of each group say that scientists understand the effects of GM foods at least fairly well.
As noted above, those who care a great deal about the issue of GM foods are also a bit more likely than others to see scientists as agreeing that GM foods are generally safe to eat. Americans are, comparatively speaking, more trusting of information from scientists and small farm owners on the safety of GM foods than they are of information from food industry leaders, the news media or elected officials.
In absolute terms, however, Americans are somewhat skeptical of information from scientists. About one-in-five say they do not trust information from scientists at all or not too much. Public trust in information on the effects of GM foods from the news media, food industry leaders and elected officials is much lower. No more than one-in-ten Americans trust each of these groups a lot; majorities say they have no trust or not too much trust in the news media, food industry leaders and elected officials to give full and accurate information about the health effects of GM foods.
People who care more deeply about this issue express a similar level of trust in scientists as those with less concern about the issue of GM foods. However, people deeply concerned about the issue of GM foods are especially skeptical of information from food industry leaders. The public offers a mixed assessment of what influences research from scientists on GM foods.
Critics fear that genetically engineered products are being rushed to market before their effects are fully understood. Anxiety has been fueled by reports of taco shells contaminated with genetically engineered corn not approved for human consumption; the potential spread of noxious "superweeds" spawned by genes picked up from engineered crops; and possible harmful effects of biotech corn pollen on monarch butterflies. In North America and Europe the value and impact of genetically engineered food crops have become subjects of intense debate, provoking reactions from unbridled optimism to fervent political opposition.
Just what are genetically engineered foods, and who is eating them? What do we know about their benefits—and their risks? What effect might engineered plants have on the environment and on agricultural practices around the world? Can they help feed and preserve the health of the Earth's burgeoning population? Most people in the United States don't realize that they've been eating genetically engineered foods since the mids.
More than 60 percent of all processed foods on U. In the past decade or so, the biotech plants that go into these processed foods have leaped from hothouse oddities to crops planted on a massive scale—on million acres More than 50 different "designer" crops have passed through a federal review process, and about a hundred more are undergoing field trials.
Genetic modification is not novel. Humans have been altering the genetic makeup of plants for millennia, keeping seeds from the best crops and planting them in following years, breeding and crossbreeding varieties to make them taste sweeter, grow bigger, last longer.
In this way we've transformed the wild tomato, Lycopersicon , from a fruit the size of a marble to today's giant, juicy beefsteaks. From a weedy plant called teosinte with an "ear" barely an inch long has come our foot-long 0. In just the past few decades plant breeders have used traditional techniques to produce varieties of wheat and rice plants with higher grain yields. They have also created hundreds of new crop variants using irradiation and mutagenic chemicals.
But the technique of genetic engineering is new, and quite different from conventional breeding. Traditional breeders cross related organisms whose genetic makeups are similar. In so doing, they transfer tens of thousands of genes. By contrast, today's genetic engineers can transfer just a few genes at a time between species that are distantly related or not related at all. Genetic engineers can pull a desired gene from virtually any living organism and insert it into virtually any other organism.
They can put a rat gene into lettuce to make a plant that produces vitamin C or splice genes from the cecropia moth into apple plants, offering protection from fire blight, a bacterial disease that damages apples and pears.
The purpose is the same: to insert a gene or genes from a donor organism carrying a desired trait into an organism that does not have the trait. The engineered organisms scientists produce by transferring genes between species are called transgenic. Several dozen transgenic food crops are currently on the market, among them varieties of corn, squash, canola, soybeans, and cotton, from which cottonseed oil is produced. Most of these crops are engineered to help farmers deal with age-old agriculture problems: weeds, insects, and disease.
Farmers spray herbicides to kill weeds. Biotech crops can carry special "tolerance" genes that help them withstand the spraying of chemicals that kill nearly every other kind of plant. Some biotech varieties make their own insecticide, thanks to a gene borrowed from a common soil bacterium, Bacillus thuringiensis , or Bt for short.
Bt genes code for toxins considered to be harmless to humans but lethal to certain insects, including the European corn borer, an insect that tunnels into cornstalks and ears, making it a bane of corn farmers. So effective is Bt that organic farmers have used it as a natural insecticide for decades, albeit sparingly. Corn borer caterpillars bite into the leaves, stems, or kernels of a Bt corn plant, the toxin attacks their digestive tracts, and they die within a few days.
Other food plants—squash and papaya, for instance—have been genetically engineered to resist diseases. Lately scientists have been experimenting with potatoes, modifying them with genes of bees and moths to protect the crops from potato blight fungus, and grapevines with silkworm genes to make the vines resistant to Pierce's disease, spread by insects.
With the new tools of genetic engineering, scientists have also created transgenic animals. Atlantic salmon grow more slowly during the winter, but engineered salmon, "souped-up" with modified growth-hormone genes from other fish, reach market size in about half the normal time.
Scientists are also using biotechnology to insert genes into cows and sheep so that the animals will produce pharmaceuticals in their milk. None of these transgenic animals have yet entered the market.
With genetically engineered foods we minimize risks by doing rigorous testing. According to Eric Sachs, a spokesperson for Monsanto, a leading developer of biotech products: "Transgenic products go through more testing than any of the other foods we eat. We screen for potential toxins and allergens. We monitor the levels of nutrients, proteins, and other components to see that the transgenic plants are substantially equivalent to traditional plants.
Three federal agencies regulate genetically engineered crops and foods—the U. The FDA reviews data on allergens, toxicity, and nutrient levels voluntarily submitted by companies.
If that information shows that the new foods are not substantially equivalent to conventional ones, the foods must undergo further testing. Last year the agency proposed tightening its scrutiny of engineered foods, making the safety assessments mandatory rather than voluntary. In the mids a biotech company launched a project to insert a gene from the Brazil nut into a soybean.
The Brazil nut gene selected makes a protein rich in one essential amino acid. The aim was to create a more nutritious soybean for use in animal feed. Because the Brazil nut is known to contain an allergen, the company also tested the product for human reaction, with the thought that the transgenic soybean might accidentally enter the human food supply.
When tests showed that humans would react to the modified soybeans, the project was abandoned. For some people this was good evidence that the system of testing genetically engineered foods works. But for some scientists and consumer groups, it raised the specter of allergens or other hazards that might slip through the safety net.
Scientists know that some proteins, such as the one in the Brazil nut, can cause allergic reactions in humans, and they know how to test for these allergenic proteins. But the possibility exists that a novel protein with allergenic properties might turn up in an engineered food—just as it might in a new food produced by conventional means—and go undetected. Furthermore, critics say, the technique of moving genes across dramatically different species increases the likelihood of something going awry—either in the function of the inserted gene or in the function of the host DNA—raising the possibility of unanticipated health effects.
An allergy scare in centered around StarLink, a variety of genetically engineered corn approved by the U.
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