Genetically modified food may look like the answer to food shortages but the dangers might just outweigh the benefits.

But now the concern that these genetically manipulated foodstuffs are harming human health is growing. Inserting a gene into a plant’s genome is a random and haphazard process that allows no control over where the gene actually ends up in the plant’s otherwise carefully constructed DNA. Insertions can show up inside other genes, can delete natural genes or permanently turn them on or off, and can cause significant mutations near the insertion site. For instance, one study found that a gene known to be a corn allergen was turned on in GM corn, though it was turned off in its conventional parent.

“It’s genetic roulette,” says Smith. “You can create carcinogens, anti-nutrients, toxins. We don’t understand the language of DNA enough to predict what might happen. It’s an infant technology, and we’re making changes that are permanent in the gene pool of species.”