The worry about square watermelons and other misconceptions about GMO foods

As early as this week, the House is expected to vote on a bill that would require most foods containing genetically engineered ingredients to be identified as such. The Senate passed the proposed legislation last week, just a few days after Vermont became the first state to require written labels on foods known as GMOs.

If the House bill is passed, it will move Americans closer to what they have said they want: more transparency about how the genes of foods they are about to eat have been manipulated. But dispelling confusion over so-called genetically modified organisms may be impossible for any labeling scheme. As lawmakers hash out the details, here are some popular misconceptions.

— The new labels will make clear what has been genetically engineered.

Actually: Consumers may need to scan a package to see whether something in it was genetically modified, but even then they are unlikely to learn which traits were altered and why.

At the most basic level, a GMO is a plant or animal whose DNA was directly altered in a laboratory, often by inserting genes from a distant species into its cells with the help of a bacterium or one of several other tools. Many major food manufacturers are loathe to put the words "genetic engineering" on labels for fear that they will convey an impression that the foods are suspect. Under the proposal in Congress, manufacturers could instead label packages with a symbol denoting genetically engineered ingredients, or a "quick response" (QR) code that people with smartphones could scan to retrieve the information.

But manufacturers would not be required to provide information on how a food was modified or why. That a certain Hawaiian papaya, for instance, was inoculated against a virus that threatened to destroy the crop with the insertion of a gene from that virus would be impossible to tell from a generic label indicating that it had been "produced with genetic engineering." You also wouldn't know, say, that the soy lecithin in your ice cream was made from soybeans endowed with a bacterial gene that lets them thrive even when sprayed with a widely used weed-killer.

— GMO-free oats are better than the alternative.

Actually: There is no alternative. Stores do not sell genetically modified oats because they don't exist.

A non-GMO label, for example, has been added to the iconic white and gold aluminum cans of McCann's Irish Steel Cut Oatmeal, which is among the tens of thousands of products certified in recent years by the Non-GMO Project. But nothing has changed about the oats inside. Some flavored oatmeals may have been made with genetically modified ingredients. But as with the proliferation of fat-free or gluten-free labels on products (like water) that never had either, the GMO-free label does not mean a genetically engineered version of the same product is available.

— GMO labels highlight a documented health risk.

Actually: These are not warning labels. The scientific consensus is that genetically engineered crops are as safe to eat as any other crop.

In a 2014 Pew Research Center survey, just 37 percent of American adults believed genetically modified foods were safe to eat. Yet this spring the National Academies of Sciences, Engineering and Medicine reported finding "no differences that would implicate a higher risk to human health" from GMO crops. There was no evidence that GMOs in North America, where they have been part of the diet since 1996, had contributed to a higher incidence of cancer, obesity, diabetes, kidney disease, autism, celiac disease or food allergies, in comparison with Western Europe, where GMOs are rarely eaten.

Several other regulatory, scientific and health organizations have also concluded that GMOs are safe to eat. And the Food and Drug Administration warned last fall that it would consider a label false or misleading if it implied that a food was "safer, more nutritious or otherwise has different attributes" than comparable foods because it was not genetically engineered.

That doesn't mean it's impossible to engineer a plant or animal that would be bad for you. It has been done at least once, with a soybean that was not released for commercial use because its allergenic property was discovered in a routine screening. The risks of every genetically engineered crop, the 420-page National Academies report emphasized, should be evaluated individually.

— White strawberries have been altered.

Actually: Nope, they were created through old-fashioned crossbreeding.

"Every week or so I see a tweet about GMO strawberries," said Karl Haro von Mogel, a co-founder of Biology Fortified, a nonprofit website that publishes articles about genetic engineering. About 40 percent of respondents in a 2013 New York Times/CBS poll of American adults said they thought "most" or "a lot" of fresh fruits and vegetables were genetically engineered.

But except for a few fruits and vegetables, our produce is generated through older breeding methods that do not fall under government regulations governing genetically engineered crops, and would not need to be labeled.

Japanese geneticists made seedless watermelons in the 1930s, for instance, by exposing watermelon seeds to chemicals that doubled their usual pair of chromosomes, and crossing those with pollen from a regular watermelon. It is because their offspring had an odd number of chromosomes that they could not make seeds of their own, not the result of any foreign DNA.

And the popular red grapefruit now grown in Texas is the descendant of one of thousands of mutants produced by a breeder in the mid-1960s by bombarding pink grapefruit tree buds with radiation, a technique for accelerating evolution that has yielded new varieties in dozens of crops, including barley and rice. The crops created through that method, called mutagenesis or radiation breeding, can be certified organic.

And if genetic mutation sounds scary, it's worth remembering that genetic mutations happen constantly in nature without any human intervention. Orange carrots, for instance, arose from a natural mutation and became prevalent only because humans planted them. Those purple and yellow ones you might peg as GMOs were the originals. As for those white pineberries, breeders crossed two species of strawberry to create a hybrid with some of the characteristics of both — combining the genetic diversity that exists in both species.

— GMO wheat may be responsible for gluten sensitivity.

Actually: GMO wheat is not sold to the public.

The internet is full of blog posts and Twitter posts blaming GMO wheat for gluten sensitivity. The fundamental hole in this case is that GMO wheat is not sold to the public.

To be clear, wheat has been genetically modified. Monsanto Co. has field-tested wheat that was altered to tolerate the herbicide glyphosate. A British research institute field-tested modified wheat to repel insects. (It didn't work.) In 2014, Chinese researchers modified wheat to resist a destructive disease called powdery mildew, but just to see if they could. And Spanish researchers are testing wheat engineered to contain, yes, significantly less gluten. But none of it is on store shelves.

— Humans have been making GMOs for millenniums.

Actually: While selective breeding is a form of genetic modification, GMO refers to foods made with specific forms of modern biotechnology.

Proponents of genetic engineering in agriculture like to point out that people have been genetically modifying organisms for millenniums through selective breeding and other techniques. If you look at it that way, they say, nearly everything we eat is a GMO. But a majority of Americans have consistently said in polls that they would like labels on GMOs, apparently believing that a distinction between a product of traditional breeding methods and one produced through modern molecular biology should be made. Both the Vermont labeling law and the proposed national one define a GMO not as any crop in which the genetic material has changed over time, but as a crop that has been altered using specific forms of biotechnology that allow for the transfer of genetic material from one species to another or the insertion of synthetic or heavily modified DNA into an organism's genetic code. This genetic engineering has been possible for only about three decades.

— If scientists change the DNA of a mushroom in a lab, it would be labeled as genetically modified.

Actually: If no DNA from another organism is added, then it may not count as genetically modified under the new labels.

If you've ever held a typical white-button mushroom in one hand while slicing it with the other, you know it takes only the faintest pressure to produce a brown mark.

But Yinong Yang, a plant pathologist at Pennsylvania State University, has engineered one that resists browning. Using a new technique, he simply deleted a bit of DNA that was already there, leaving no added DNA from another species. The Department of Agriculture told him earlier this month that it could be sold without regulatory oversight, and it's not clear whether such products would be labeled.

— Genetically engineered rice is saving the lives of malnourished children in the developing world.

Actually: The rice is still being tested.

Some proponents of genetic engineering say the technology could be used to endow crops with important traits, especially in places with high rates of malnutrition and hunger. One variety of rice has been modified with genes from corn and a common soil bacterium that together produce beta carotene, which the human body uses to make vitamin A. The lack of the vitamin causes blindness in hundreds of thousands of children in Asia and Africa each year.

The so-called golden rice, in development since the 1990s, has long been a flashpoint in the debate over genetic engineering. Several anti-GMO groups, including Greenpeace, have organized protests over it, saying, without evidence, that it could pose unforeseen risks to human health and the environment while profiting big agrochemical companies. Proponents have accused activists of essentially having blood on their hands for delaying the crop's approval: "How many poor people in the world must die before we consider this a 'crime against humanity'?" asked a letter signed by more than 100 Nobel laureates earlier this month, petitioning Greenpeace to change its stance.

But even if Greenpeace changes its stance, the rice is not ready yet. In 2013, a trial that had found a bowl of the rice supplied more than half of a child's daily vitamin A requirement was deemed to have been conducted unethically because it had not been disclosed to the participants that they were eating genetically modified rice. That set back any plans to distribute it. And last spring, the nonprofit institute responsible for the rice's development said it did not grow well enough to be embraced by farmers. Golden rice may one day help save lives. But not yet.

— Chipotle's burritos used to be stuffed with GMOs.

Actually: Only the cooking oil and the tortillas had ingredients from GMO crops.

Last year, the restaurant chain ran its "G-M-Over It" campaign to announce the elimination of GMOs from its menu. But according to the company website, only its soy cooking oil and the soy and corn in its tortillas had come from genetically modified crops. Even the corn in its roasted chili-corn salsa was not genetically modified. The GMO corn we eat usually comes in the form of syrup, starch or oil, though a small amount of sweet corn, as it is known, is also genetically engineered.

Almost all soybeans and most corn grown in the United States are modified so farmers can spray them with glyphosate (the main ingredient in Roundup) to kill weeds without harming the crop. But according to Andrew Kniss, an agronomist at the University of Wyoming, Chipotle's replacement ingredients also came from crops cultivated with weed-killers — just different ones.

— Huge chickens are GMOs.

Actually: They got that way through regular breeding.

Over the last 60 years, chickens have become bigger. They grow faster and require less food per pound of meat they produce. But despite what you may read on the internet, their DNA has not been manipulated in a laboratory. Their size results from farmers selecting and crossbreeding the ones with the most desirable qualities, and because Americans like white meat, that process has produced birds with oversized breasts that their legs can barely support.

Those chickens, like most farm animals, do eat feed made from genetically engineered corn and soybeans. But any added or modified genes, and the proteins they produce, are broken down during digestion. And the nutrients in eggs, meat and milk have been found to be the same as those from animals fed with plants that were not genetically engineered.

Some chickens have been engineered so their eggs contain an enzyme that can treat a rare disease. And some goats have also been modified to produce enzymes that are lacking in some humans. But the animals that generate these "farmaceuticals" are not sold for human consumption. And the only genetically modified animal to be approved for sale in the United States, a salmon engineered to grow faster to its market size, is not yet available.