OTTAWA (CP) - The Ontario government will intervene in the Supreme Court battle over gene patents, which pits biotech giant Monsanto against Saskatchewan farmer Percy Schmeiser.

While Schmeiser and his backers are concerned with protecting the rights of farmers, Ontario is worried about how gene patents could affect health costs. Ontario's affidavit to the Supreme Court says Schmeiser's case "has important implications for the development of public policy in Ontario including the delivery of health care to its residents."

Monsanto sued Schmeiser several years ago for allegedly growing herbicide-resistant canola in violation of its patent of the gene. Monsanto won in two lower-court decisions but Schmeiser is appealing to the Supreme Court.

His case has become an international cause celebre, with donations pouring in from around the world.

Ontario got involved in the genetic patenting issue when a U.S. company, Myriad Genetics, threatened to sue the province for not paying royalties on tests for genetic predisposition to breast cancer.

Myriad claims a patent over certain genes responsible for cancer, and its test costs three times as much as the one Ontario uses.

"That's the first of probably many genetic tests," said Sara Blake of the Ontario Ministry of the Attorney General, in an interview Tuesday. "It's about health care."

Schmeiser, backed by environmentalists and anti-globalization groups, is arguing that no one can patent genes, since they are natural life forms rather than human inventions.

Ontario is arguing that a gene molecule is patentable but not the genetic information contained in the molecule.

Ontario has previously requested but failed to get clarification of the issue from the federal government, said Nadege Adam of the Council of Canadians.

"They (Ontario) asked that it be clearly put in law that one cannot patent a gene, and the government washed their hands of it and refused to get involved. Now the Ontario government sees an opportunity to address that issue and put it into law."