Jun. 4--WASHINGTON -- Rapid advances in biology and genetics are raising fresh concerns about the spreading practice of patenting human genes.

The U.S. Patent and Trademark Office has granted patents to at least 4,382 human genes, including genes related to Alzheimer's, asthma, cancer, muscular dystrophy and other serious diseases.

"Twenty percent of the human genes are currently patented," said Christopher Hansen, an attorney for the American Civil Liberties Union, which filed a suit last month challenging six patents on two genes that are connected to tests for breast and ovarian cancer.

A gene patent gives its owner the exclusive right, for up to 20 years, to control its use for medical research, diagnosis or treatment.

"A gene patent holder has the right to prevent anyone from studying, testing or even looking at a gene," the ACLU lawsuit protests. "As a result, scientific research and genetic testing has been delayed, limited or even shut down due to concerns about gene patents."

Patent holders reply that they have a constitutionally guaranteed right to protect their inventions in order to pay the heavy costs of genetic research and development.

Though gene patents are lawful, many scientists, health professionals and patients' organizations object that the patents are stifling research and interfering with patient care.

"Patents are meant to protect inventions, not things that exist in nature like genes in the human body," Hansen said.

"Questionable patents are too easily obtained and are too difficult to challenge," the Senate Committee on the Judiciary declared last month. "An industry has developed in which firms use patents not as a basis for producing and selling goods but, instead, primarily for obtaining license fees."

The patent war is being waged on several fronts.

Congress is weighing legislation that would make it easier to challenge patents. The National Institutes of Health released a 136-page draft report on the problem this spring. The National Academy of Sciences and the Federal Trade Commission have held multiple hearings.

The ACLU suit was filed in federal district court in Manhattan on behalf of the American College of Medical Genetics, the College of American Pathologists, other research organizations and individual patients. The defendants are Myriad Genetics, a pharmaceutical firm in Salt Lake City, and the University of Utah Research Foundation, which sponsored the research.