Many people smarter than I am are saying genetically modified organisms or GMOs are safe, yet I'm still skeptical. And when I say smarter, I'm talking Nobel laureate-smarter. More than 110 Nobel laureates are urging Greenpeace to stop a campaign against genetically modified organisms. Forty-one of them have won the Nobel Prize for Medicine.

Although a federal study by the National Academy of Sciences has declared GMOs safe for human consumption, Greenpeace doesn't believe there's "adequate scientific understanding of their impact on the environment and human health."

The laureates believe differently. They presented a letter at a news conference last week in Washington, saying "genetically modified foods are safe to eat" and a "safe way to meet the growing demands of an increasing global population," according to Tech Times. The group is keeping a tally of scientific supporters and offering the reasons behind that support.

There are scientific studies to back up the premise that GMOs are safe, too. Yet I'm still skeptical.

Why? Because there so many unanswered questions, and here are just a few that bother me:

Why do so many other countries ban GMOs or demand labeling?

Last fall, 19 European countries, including Austria, Northern Ireland, France and Germany, opted out of cultivating some or all GMOs, according to EcoWatch, a website devoted to environmental news and sustainable living. I have to believe these countries have scientists who are advising politicians on health and environmental issues surrounding GMOs. What did they find that convinced those countries to be so cautious when it comes to GMOs?

There are 64 countries that require GMO labeling. Again, I have to believe they have reasons, backed by studies and scientific reports, for requiring this. Why do officials in these countries see this so differently than officials here in the United States?

Why have food allergies seemingly exploded since the introduction of GMOs?

I understand correlation does not equal causation, but the increase in food allergies over the past several decades has to be caused by something. Is it possible that a link between GMOs and food allergies hasn't been found yet? I often think of the question food activist Robyn O'Brien frequently asks, "Are we allergic to food or what's been done to it?”

What growing conditions are GMOs studied under?

Many GMOs have been developed to resist the chemical weed killer glysophate. The World Health Organization believes glysophate is probably carcinogenic for humans, and just this past spring, the FDA decided to look into glysophate residue on foods. If the FDA is looking into it, officials there must have some concerns, right?

So I wonder if the scientists who study GMOs study the end result of the GMOs — the foods grown by farmers who used glysophate. It would seem to me there would be a difference between food grown from GMO seed where glysophate or other chemicals weren't applied and food grown from GMO seed that did have those chemicals applied.

Maybe, just maybe, GMOs are safe if grown under natural or organic conditions and not safe when grown using chemical pesticides. I realize that could work for non-GMO foods, too, but when the seeds are bred to resist the chemicals, the opportunity is there for a careless amount of chemicals to be applied.

Why is there such resistance to labeling GMOs?

GMOs are labeled in 64 other countries, yet there has been a concerted effort by GMO producers, food manufacturers and members of Congress to block this specific labeling in the U.S. Although 90 percent of Americans want GMOs labeled on food packaging, hundreds of millions of dollars have been spent to prevent that from happening.

The issue isn't going away. The public isn't backing down on its demands, and some food manufacturers like Campbell's and General Mills have said they will label GMOs on food packaging, but Congress can't stop trying to pass a law making labeling voluntary and difficult. They would like to adopt a voluntary SmartLabel that would go on food packaging and need to be scanned by a smartphone to find out information. People without technology would not have access to the information.

This huge push and the millions of dollars spent to keep the information out of the hands of consumers is a huge red flag to me. It makes me suspicious that something is being hidden — something big.

Do these questions make me anti-GMO?

These questions are the reasons I'm skeptical about the safety of GMOs. I'm not ready to declare myself anti-GMO, but I am ready to say I don't believe there's enough time-tested, accurate information out there for me to be comfortable saying I'm pro-GMO.

I'm definitely pro-GMO labeling though. With all of these uncertainties, I believe consumers should have the ability to opt out of eating GMOs, and the only way to do that is with proper food labeling.

Robin Shreeves ( @rshreeves ) focuses on food from a family perspective from her home base in New Jersey.