When does a person's body not completely belong to that person? When the United States Patent and Trademark Office awards patents for human genes, that's when. But a court ruling could make all that change.

Myriad Genetics (Nasdaq: MYGN) holds patents on two genes, BRCA1 and BRCA2, and for the next 20 years that company is the only entity that has the rights to those genes -- including, even, the people within whom those genes reside. Those BRCA genes are particularly important because they've been associated with hereditary forms of breast and ovarian cancer. Their purpose is to suppress cancerous tumors. Mutations in the genes, though, can indicate a higher risk of cancer. Myriad has developed tests for those mutations. Because it owns the exclusive rights to those genes -- not just the test -- the company can prevent anyone else from testing, studying, or even looking at them. If you want to be tested, you have to go through Myriad. Period.

The BRCA genes aren't the only parts of the human body not completely belonging to … well, their human owners. About 20% of the human genome has already been patented, and nearly half of it by private companies -- including genes associated with muscular dystrophy and heart attacks. Thanks to recent acquisitions, Quest Diagnostics (NYSE: DGX) holds both of those patents. Bio-Rad (NYSE: BIO) owns those related to hemochromatosis, a disorder that causes your body to absorb too much iron. And that's just the tip of the iceberg. Incyte (Nasdaq: INCY) alone holds approximately 2,000 human gene patents.

See you in court
But all that may end. Last year, a U.S. District Court judge struck down those BRCA patents in a suit from the American Civil Liberties Union and others, which argued that genes fall outside the realm of patentable things. The judge agreed, ruling that the patents were "improperly granted" because they involved a "law of nature." Myriad is appealing that decision, and I wouldn't be surprised to see this case pushed all the way up to the Supreme Court.

Another medical patent case is already on the high court's docket and could have an impact on the Myriad case. The justices will hear an appeal from the not-for-profit Mayo Clinic challenging the validity of Prometheus Laboratories' two patents relating to the testing for and treatment of gastrointestinal disorders. Mayo claims that Prometheus cannot have the sole right to observe a natural phenomenon -- in this case, how the body reacts to certain drugs.

All health-sciences companies that rely on patent protections will be watching these cases closely. Genomic Health (Nasdaq: GHDX) wrote in an amicus brief to the Supreme Court in a 2009 case that without patent protections it would have a harder time obtaining the funding needed for future research in personalized medicine and that, in the end, patients will suffer.

In regard to the BRCA gene testing, right now Myriad charges around $3,000 for performing those tests. If the company loses the case and those genes enter the public domain, there are geneticists out there saying they could charge $300 or less. This high-risk industry has a right to be worried.

Add Myriad Genetics, Quest Diagnostics, Bio-Rad,  Incyte, and Genomic Health to your Watchlist.

Fool contributor Dan Radovsky owns no shares in any of the companies named above. Motley Fool newsletter services have recommended buying shares of Quest Diagnostics and Genomic Health. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.