WASHINGTON — In a lively hearing Monday, the Supreme Court struggled to find a narrow way to rule on the momentous question of whether human genes may be patented.
“Why should we jump in and decide the broadest possible question?’’ asked Justice Samuel A. Alito Jr.
In order to simplify the complex scientific and legal questions before them, the justices proposed more simple analogies — to chocolate chip cookies, baseball bats, and plants in the Amazon with medicinal qualities. But none of them proved wholly satisfactory, and Justice Stephen G. Breyer said there was a lesson in that.
“The patent law is filled with uneasy compromises,’’ he said.
Some justices expressed concern about making sure that businesses continue to engage in expensive research. Others worried that allowing genes to be patented would shut down innovation.
“Why would a company undertake massive investment if it cannot patent?’’ asked Justice Antonin Scalia.
But Justice Sonia Sotomayor suggested that an isolated gene is ‘‘just nature sitting there.’’
The court’s ruling in the case will shape the course of scientific research and medical testing and will affect willingness of businesses to invest in expensive work in isolating and understanding genetic material.
The case concerns patents held by Myriad Genetics, a Utah company, on genes that correlate with increased risk of hereditary breast and ovarian cancer. The decision in the case could affect not only thousands of patented genes but also pharmaceuticals, vaccines, and genetically modified crops.
The central question for the justices in the case was whether isolated genes are ‘‘products of nature’’ that may not be patented or ‘‘human-made inventions’’ eligible for patent protection.
The patents were challenged by scientists and doctors who said that their research and ability to help patients had been frustrated. Lower courts held that all but one of them, Dr. Harry Ostrer, lacked a stake in the case direct enough to give them standing to sue.
Christopher A. Hansen, a lawyer for Ostrer with the American Civil Liberties Union, said Myriad deserves credit for its work but not a patent. ‘‘What exactly did Myriad invent?’’ Hansen asked. ‘‘The answer is nothing.’’
A lawyer for the company, Gregory A. Castanias, said the genes do not occur in nature and were isolated thanks to human ingenuity.
In a unanimous decision last year, the Supreme Court said that medical tests relying on correlations between drug dosages and treatment are not eligible for patent protection. Natural laws, Breyer wrote for the court, may not be patented standing alone or in connection with processes that involve ‘‘well-understood, routine, conventional activity.’’
Solicitor General Donald B. Verrilli Jr., representing the federal government, largely supported Ostrer and said last year’s decision suggested that the correct answer in the new one was that merely isolating a gene was not sufficient for patent protection. Manipulating a gene to create something not found in nature, he added, would be.
Last year, a divided three-judge panel of a federal appeals court in Washington ruled for Myriad. Each judge issued an opinion, and a central dispute was whether isolated genes are sufficiently different from ones in the body to allow them to be patented.
The Supreme Court’s ruling, which is expected this summer, could have wide implications for the multibillion-dollar biomedical industry and the fight against diseases such as breast and ovarian cancer.
Abstract ideas, natural phenomena, and laws of nature cannot be awarded patents, which give inventors the right to prevent others from making, using or selling a novel device, process or application.
The US Patent and Trademark Office has been awarding patents on human genes for almost 30 years, but opponents of Myriad Genetics’s patents on two genes linked to an increased risk of breast and ovarian cancer say such protection should not be given to something that can be found inside the human body.
Myriad says DNA it isolated from the body has a ‘‘markedly different chemical structure’’ from DNA within the body.
‘‘What was ‘merely snipped’ out of the body here is fundamentally different in kind from what was in the body,’’ Castanias said. ‘‘The most important reason it’s different in kind is that it cannot be used in the body to detect the risk of breast and ovarian cancers.’’
The company has used its patent to develop its BRACAnalysis test, which looks for mutations on the breast cancer predisposition gene, or BRCA. Those mutations are associated with much greater risks of breast and ovarian cancer.
Myriad sells the only BRCA gene test. Opponents of its patents say the company can use its patents to keep other researchers from working with the BRCA gene to develop other tests.
Several justices reacted to the argument that patents are crucial to scientific discoveries because they allow companies to recoup their investments.
‘‘Why shouldn’t we worry that Myriad or companies like it will just say, ‘Well, you know, we’re not going to do this work anymore?' ’’ Justice Elena Kagan asked.