All this may sound absurd, but it is the heart of a case that will be argued before the Supreme Court on Tuesday. In 1986 researchers filed a patent application for a method of testing the levels of homocysteine, an amino acid, in the blood. They went one step further and asked for a patent on the basic biological relationship between homocysteine and vitamin deficiency. A patent was granted that covered both the test and the scientific fact. Eventually, a company called Metabolite took over the license for the patent.

Although Metabolite does not have a monopoly on test methods  other companies make homocysteine tests, too  they assert licensing rights on the correlation of elevated homocysteine with vitamin deficiency. A company called LabCorp used a different test but published an article mentioning the patented fact. Metabolite sued on a number of grounds, and has won in court so far.

But what the Supreme Court will focus on is the nature of the claimed correlation. On the one hand, courts have repeatedly held that basic bodily processes and "products of nature" are not patentable. That's why no one owns gravity, or the speed of light. But at the same time, courts have granted so-called correlation patents for many years. Powerful forces are arrayed on both sides of the issue.

In addition, there is the rather bizarre question of whether simply thinking about a patented fact infringes the patent. The idea smacks of thought control, to say nothing of unenforceability. It seems like something out of a novel by Philip K. Dick  or Kafka. But it highlights the uncomfortable truth that the Patent Office and the courts have in recent decades ruled themselves into a corner from which they must somehow extricate themselves.

For example, the human genome exists in every one of us, and is therefore our shared heritage and an undoubted fact of nature. Nevertheless 20 percent of the genome is now privately owned. The gene for diabetes is owned, and its owner has something to say about any research you do, and what it will cost you. The entire genome of the hepatitis C virus is owned by a biotech company. Royalty costs now influence the direction of research in basic diseases, and often even the testing for diseases. Such barriers to medical testing and research are not in the public interest. Do you want to be told by your doctor, "Oh, nobody studies your disease any more because the owner of the gene/enzyme/correlation has made it too expensive to do research?"