American farmers have been growing genetically modified crops for years, from seeds engineered to resist pests and chemicals. These patented seeds produced bigger crops and profits for farmers who bought them from companies like DuPont and Monsanto, but for other farmers the seeds have created a host of problems. CBS News Chief Investigative Correspondent Armen Keteyian has been investigating.
David Runyon and his wife Dawn put a lifetime of work into their 900-acre Indiana farm, and almost lost it all over a seed they say they never planted.
"I don't believe any company has the right to come into someone's home and threaten their livelihood," Dawn said, "to bring them into such physical turmoil as this company did to us."
The Runyons charge bio-tech giant Monsanto sent investigators to their home unannounced, demanded years of farming records, and later threatened to sue them for patent infringement. The Runyons say an anonymous tip led Monsanto to suspect that genetically modified soybeans were growing on their property.
"I wasn't using their products, but yet they were pounding on my door demanding information, demanding records," Dave said. "It was just plain harassment is what they were doing."
Today, Monsanto's patented "Round-up Ready" soy commands the lion's share of the genetically-modified soybean seed market, its genetic code manipulated to withstand the company's popular weed killer.
But the promise of fewer weeds and greater production comes with a hefty fee. Farmers must sign an iron-clad agreement not to re-plant the harvested seed, or face serious legal consequences - up to $3 million in damages.
"It's about protecting the patent, defending the patents, so farmers have the protection and can use these technologies over time," said Monsanto spokeswoman Tami Craig Schilling.
The Runyons say they signed no agreements, and if they were contaminated with the genetically modified seed, it blew over from a neighboring farm.
"Pollination occurs, wind drift occurs. There's just no way to keep their products from landing in our fields," David said.
"What Monsanto is doing across the country is often, and according to farmers, trespassing even, on their land, examining their crops and trying to find some of their patented crops," said Andrew Kimbrell, with the Center For Food Safety. "And if they do, they sue those farmers for their entire crop."
In fact, in Feb. 2005 the Runyons received a letter from Monsanto, citing "an agreement" with the Indiana Department of Agriculture giving it the right to come on their land and test for seed contamination.
Only one problem: The Indiana Department of Agriculture didn't exist until two months after that letter was sent. What does that say to you?
"I'm not aware of the specific situation in Indiana," Schilling said.
"I'm just talking in general terms," said Keteyian. "Would Monsanto lie, deceive, intimidate, harass American farmers to protect its patents?"
"With farmers as customers I would say that is not our policy by any means."
74-year-old Mo Parr is a seed cleaner; he is hired by farmers to separate debris from the seed to be replanted. Monsanto sued him claiming he was "aiding and abetting" farmers, helping them to violate the patent.
"There's no way that I could be held responsible," Parr said. "There's no way that I could look at a soy bean and tell you if it's Round-up Ready."
The company subpoenaed Parr's bank records, without his knowledge, and found his customers. After receiving calls from Monsanto, some of them stopped talking to him.
"It really broke my heart," Parr said. "You know, I could hardly hold a cup of coffee that morning,"
Monsanto won its case against Parr, but the company, which won't comment on specific cases, has stopped its legal action against the Runyons.
And now four states, including Indiana, prohibit seed suppliers from entering a farmer's property without a state agent, tactics which have threatened a way of life.