It’s a growing controversy: Should GMO foods always be labeled so consumers are aware that the product contains genetically modified ingredients?

GMOs—or genetically modified organisms—are created in a lab by altering the genetic makeup of a plant or an animal. Ninety-two percent of Americans believe that GMO foods—widely found in kitchens across the country—should be labeled before they’re sold, according to a recent nationally representative survey of 1,004 people from the Consumer Reports National Research Center. (Last year our tests discovered that GMOs were present in many packaged foods, such as breakfast cereals, chips, baking mixes, and protein bars.)

Demand for non-GMO foods has skyrocketed: In 2013, sales of non-GMO products that were either certified organic (by law, organic products can’t be made with GMO ingredients) or that carried the “Non-GMO Project Verified” seal increased by 80 percent, according to the Nutrition Business Journal. It has prompted a growing number of companies to avoid using GMOs in new products or to voluntarily reformulate existing ones so that they can sport reliable non-GMO labels. PepsiCo, for example, sells Stacy’s Simply Naked bagel and pita chips with the Non-GMO Project Verified seal; General Mills, which introduced a non-GMO original Cheerios cereal early last year, also has the non-GMO product lines Cascadian Farm and Food Should Taste Good.

Yet GMO labeling has become a hot-button issue: Vermont passed a GMO labeling law last April. Last fall, the question of whether food manufacturers should be required to list GMO ingredients on their product labels was put to voters in Colorado and Oregon. On both sides were strong arguments and a lot of money spent—mostly on the part of food and chemical industry opponents to labeling. (In the Colorado election, for example, they outspent labeling supporters by about 16 to 1.) The measure was rejected in Colorado, and it failed in Oregon by a razor-thin margin in a recount—837 votes.

In an interesting twist, some food companies that expressed strong opposition to such mandatory labeling are the same ones turning out new non-GMO products. “They are experimenting, in case labeling does become mandatory and boosts demand for non-GMOs,” says Nathan Hendricks, Ph.D., an agricultural economist at Kansas State University. “Of course, they may do this without too much fanfare to avoid raising questions about why they’re removing GMOs from some of their products but not others.”

With so many voices in the conversation and products on the market, how can you make buying decisions that are best for you and your family? Our Q&A helps you separate fact from fiction.

Are GMOs bad for my health?

Those who support using GMOs point out that Americans have been eating foods containing them for more than 15 years and that there’s no credible evidence that people have been harmed. But saying there’s no evidence of harm isn’t the same as saying they’ve been proved safe. “The contention that GMOs pose no risks to human health can’t be supported by studies that have measured a time frame that is too short to determine the effects of exposure over a lifetime,” says Robert Gould, M.D., president of the board of Physicians for Social Responsibility.

A joint commission of the World Health Organization and the Food and Agriculture Organization of the United Nations has established a protocol for evaluating the safety of GMOs, which it says have the potential to introduce toxins and new allergens (or increase levels of existing ones), or cause nutritional changes in foods and other unexpected effects. Other developed nations have used those guidelines in their mandatory premarket safety assessments for genetically modified organisms. But the Food and Drug Administration doesn’t require any safety assessment of genetically engineered crops, though it invites companies to provide data for a voluntary safety review.

Animal studies—commonly used to help assess human health risks—have suggested that GMOs might cause damage to the immune system, liver, and kidneys. More studies are needed to determine long-term effects. And the ability of researchers to track potential health effects of GMOs in the human population is hampered by the absence of labeling. “Physicians need to know what their patients are eating,” Gould says. “If your patient has a problem with food allergies or other side effects that may be related to GMOs, it’s difficult to identify any links unless these foods are labeled.”