Percy Schmeiser is a Canadian farmer who grows canola. Each year since 1947 Percy and his wife saved the best of their crop, slowly breeding seed adapted to their part of the Canadian plains.

All that ended with a surprise letter.

The letter was from Monsanto. It accused the farmers of "stealing" Monsanto's patented seed, a genetically modified (GM) version of canola. Percy and his wife would have to pay the world's largest producer of GM crops for use of their product.

The Schmeisers had not used Monsanto's seed. Surely there had been a mistake. But no.

The canola farmers had been afflicted with something known as "genetic drift," the billowing of seedmatter by wind from neighboring farms onto their own land.

Canada's high court ruled that the patent law supersedes the rights of any and all farmers. If Monsanto plants were found on the Schmeisers' farm, then they should pay. (Farmers in the U.S. have faced similar legal battles.)

Not long ago I heard Percy tell his story. He spoke of the tremendous stress his family had endured, the debt they incurred, and the breakdown of their rural social fabric as neighbor farmers who stood up for them received the same Monsanto letter.

"The right of farmers to use seeds from year to year should never be taken away," he said, in clipped brogue. "Some of the best wheat we have in Canada is developed by farmers, not companies."

The issue, however, is bigger than the property rights of farmers.

Genetically modified organisms (GMOs) have been engineered through DNA to take on new characteristics. Corn, for example, may be encoded to resist herbicides (such as Roundup Ready varieties.) Others, like Bt cotton, defy insects. Bacteria and viruses are often used in engineered plants.

Many people believe that genetic meddling is humans playing God, and that America embraced GMOs without taking the time to fully understand negative ramifications.

GMO foods have not been around a sufficient time for us to know their repercussions on the human body.

Mendicino County, California was the first in the U.S. to ban GMOs, in 2004, followed by many others. Other places, including Europe, require labeling.

There is good news. Recently Percy Schmeiser won his legal appeal and Monsanto has to pay the costs of cleaning up his contaminated field.

Janisse Ray, author of Ecology of a Cracker Childhood, is a gardener and a seed-saver.