Dmitry Naumov / Featurepics.com

California voters will decide whether genetically modified foods should be labeled as such.

If you saw a “genetically engineered” label on a box of cereal, bag of chips, or package of tofu -- would you buy the product?

That’s a question many wonder as California voters prepare to vote on Proposition 37 next Tuesday. If approved, food manufacturers will be required by law for the first time to label all products produced from genetically modified (GM), biotech, or genetically engineered (GE) crops. “Natural,” “naturally made, “naturally grown,” and “all natural” would also be prohibited on labels and advertisements of GM foods.

Previous efforts to mandate the labeling of GM foods have failed in both Connecticut and Vermont.  

Introduced commercially in the mid-1990s, GM crops are those in which DNA—the genetic material of an organism—is transferred from one organism to another in order to introduce a new trait into the organism. The resulting crops would then be disease- or pest-resistant, or be more tolerant to herbicides.

Organizations including the World Health Organization and the National Academy of Sciences believe GM foods pose no likely health risk, and proponents of the technology cite benefits including reduced cost to produce crops and increased crop yield; decreased pesticide and herbicide use; and more nutritious crops.

But critics such as the American Academy of Environmental Medicine cite evidence, primarily from animal studies, of possible health risks of GM food consumption including infertility, organ damage, gastrointestinal and immune system disorders, and accelerated aging. They also cite inadequate safety testing, although an extensive 2010 review of 50 research projects done over a decade by the European Commission found no evidence to link consumption of GM foods with higher risks of food or feed safety when compared with conventionally produced foods.

Although the FDA encourages biotech companies to voluntarily consult with them about the safety of their products before making them available to consumers, GM foods don’t need to be labeled unless they have significantly different nutritional properties, contain allergens not normally expected in the food, or contain toxins beyond acceptable amounts.

Because there’s no mandatory labeling of GM foods, there’s a good chance many of us consume them without even knowing. According to the Grocery Manufacturers Association, 75 to 80 percent of conventional processed foods currently contain GM ingredients. Among the foods most likely to contain GM ingredients include ready-to-eat cereals, snack chips, tofu and other soy-derived foods, soups, and any processed foods made with corn, soybeans, canola and cottonseed oils.

Those who support the “Yes to Prop 37” campaign believe that consumers should not be left in the dark about what’s in their food. According to one such advocate, Michele Simon, JD, MPH, author of "Appetite for Profit," “Prop 37 is an important step toward bringing America in line with 61 other nations that already require some form of GM labeling.” She also questions what she refers to as “The more than $40 million spent by leading pesticide and junk food companies to keep Californians in the dark about what they’re eating.”

Although it doesn’t support mandatory labeling, the American Medical Association recently updated their position on GE foods and called for mandatory safety testing before they hit the market.

While the Academy of Nutrition and Dietetics’ official evidence-based position on GM foods won’t be available until 2013, registered dietitian and Academy spokesperson Jeannie Gazzaniga-Moloo, Ph.D, R.D. says, “The Academy supports consumers right to know what ingredients are in the foods they purchase to feed their families.” She adds, “Those who have specific questions about foods or ingredients should contact food manufacturers directly.”

Although it’s unclear when and if all GM foods will be labeled, some consumers want to minimize their exposure. Here's what you can do:

Consider going organic, at least sometimes
According to the U.S Department of Agriculture, a food that’s labeled “organic” cannot be produced through genetic engineering. Although some organic foods unintentionally contain small amounts of GM ingredients, choosing more organic foods—especially processed ones made with corn, soybeans, canola and cottonseed oils that are more likely than many other processed foods to contain GM ingredients —can help you reduce your overall exposure. And even though there may not be enough evidence to say organic foods trump conventional ones nutritionally, a recent review in Annals of Internal Medicine found that consuming organic foods may reduce exposure to both pesticide residues and antibiotic-resistant bacteria.

Be picky with processed foods
To minimize your exposure to GM foods, look for processed foods that have a “Non-GMO Project Verified Seal” on their label. Created by The Non-GMO Project, a non-profit organization in North America; the seal indicates the product has been produced “According to consensus-based best practices for GMO avoidance.”

Mix it up
Because organic foods can be pricey, choose seasonal, local items and buy appropriate amounts based on what your family typically eats to save money and reduce waste. If you can’t afford or choose not to buy all organic food, vary your grocery list and menus weekly or monthly. For example, buy different kinds of beans, whole grains, and oils—that’ll help you vary your nutrient intake, and at the same time, minimize possible health risks associated with individual foods.

For more information on GMOs, check out the World Health Organization website and The PEW initiative on Food and Biotechnology  

More from NBCNews.com Health:

• Flu shot may protect you from a heart attack
• Greenpeace out to sea on GM rice issue, bioethicist says
• Closing schools during flu outbreak can lessen ER visits

Courtesy the Lovett family

Diana and Matt Lovett of Larchmont, N.Y., rely on organic baby food for their son, Noam, 4 1/2 months, primarily because it contains no pesticides.

If you’re buying organic foods for your kids because you think they’re more nutritious, you might want to think again. The nation’s pediatricians have weighed in on the issue for the first time, and they say that when it comes to nutritional value, organics are virtually indistinguishable from conventionally produced foods.

“Pretty much every study shows no nutritional difference,” said Dr. Janet Silverstein, a professor of pediatric endocrinology at the University of Florida. She’s a co-author of the report published Monday by the American Academy of Pediatrics. 

Silverstein and her colleagues reviewed the available studies on organic and conventionally produced foods, including produce, dairy products and meat. They considered research about issues including nutrition, hormones, antibiotics and synthetic chemical exposure, plus factors such as environmental impact and price.

Overall, the docs came to a conclusion that may surprise some parents who believe organic is best for their kids

“In the long term, there is currently no direct evidence that consuming an organic diet leads to improved health or lower risk of disease,” AAP officials said in a statement.

No large studies been conducted that address the differences, they said. That largely echoes the findings of a Stanford University review last monththat analyzed 237 studies and concluded that organic foods were no more nutritious than conventional -- and ignited huge debates online and on talk shows.

When it comes to the pesky issue of pesticides, hormones and other contaminants, the pediatricians came to a similar conclusion.

No one knows yet whether those substances make foods from conventional sources less safe for growing kids, Silverstein said.

While there’s no question that conventionally grown foods have more pesticides than organic foods, the effect isn’t certain.

“They are at low levels -- certainly lower than the federal government regulatory cutoffs and lower than is thought to be dangerous for adults,” Silverstein said. “However, we don’t know the effect of these low levels on children during the vulnerable period of time when brain growth is occurring: in utero and through the first few years of life.”

Studies evaluating the long-term effects of pesticides on child development need to be conducted, she said.

“Until we know the answer to that question, we can’t really give people good advice other than to let them know what is known and what still needs to be studied,” she added.

One clear difference between organics and conventionally produced food is price. Organics are typically more expensive, in some cases priced 50 percent higher than the same conventionally grown foods.

Parents should recognize the importance of providing kids with lots of fruits and vegetables whether it comes from organic or conventional farms.

“If a parent has limited resources, the most important thing is to give the child a healthy diet and not to give fewer fruits and vegetables because they’re spending more on organic foods,” Silverstein said.

If cost is a factor, families can be selective in choosing organic foods, Silverstein said. Some conventionally grown fruits and vegetables tend to have lower pesticide residues. The AAP cites organic shopper's guides like those provided by Consumer Reports and the Environmental Working Group as references for consumers.

If moms interviewed by NBC News are typical, the new report isn’t likely to dissuade any parents from buying organic.

For Diana Lovett, 34, of Larchmont, N.Y., the most important issue was avoiding pesticides in the foods she gives her son, Noam, 4 ½ months.

“We started him on organic baby food and we’re really happy with it. I just wanted something healthy for my son and didn’t like the idea of pesticides in baby food,” she said.

Lovett says she’d make her own baby food if she couldn’t find an organic product at the supermarket.  “If I could I would grow my own fruits and veggies,” Lovett said. “Organic just feels one step closer to that.”

Gigi Lee Chang, 45, of New York, has been feeding her son, Cato, mostly organic foods since he was a baby. Now that he’s 8, she’s planning on packing organic fruits and vegetables to supplement school lunches.

“I don’t think from a mom’s perspective it was ever about the nutrition,” said Chang, chief executive of Healthy Child, Healthy World, an advocacy group that works to help parents protect children from harmful chemicals.

As far as Chang is concerned, the science just hasn’t had a chance to catch up on this issue. Chang points to the situation with bisphenol A, the estrogen-mimicking chemical known as BPA. Several years ago there wasn’t enough evidence on the impact of BPA, she said. And now it’s been banned from baby bottles and sippy cups.

That makes sense to Rachel Blumenthal, 32, of New York. She chooses organic foods for 18-month-old Griffin’s meals because she’s worried about chemicals in conventional foods.

“It’s really more for long-term health concerns,” she said. “I just don’t want to take the chance. Years and years of cumulative exposure to pesticides can’t be good for anybody. My husband and I try to eat organic, too.”

Blumenthal figures it’s just a matter of time before scientists prove what she suspects.

“Just 20 or 30 years ago everyone was sunbathing,” she said. “Now we know it causes cancer. I anticipate that happening with all these pesticides.”            

Related stories: 

• Organic food no more nutritious than conventional, study finds 
• Trader Joe's peanut butter recalled for salmonella risk
• BPA may boost obesity in kids, study finds