In the USA, it is possible to patent parts of the human body, namely the genes. The patent holder gains the legal right to block anyone from doing research on that gene or developing any drugs which might have an effect on the gene or prohibiting any test that checks for genetic anomalies in that gene. It is similar to a legal right to stop anyone from doing any research of any kind on some other part of the human body, e.g. the knee.
Normally, a patent is awarded for developing something novel (no prior art) and non-obvious. In theory, you can’t patent something like granite or orange juice that you did nothing to create. However, the US courts are so corrupt, that they allow wealthy unscrupulous corporations like Monsanto to patent plant strains that clearly do not in any way belong to them, strains that have been in the public domain for thousands of years. All they have to do is be the first to think of patenting some pre-existing object, plant or animal. In principle, by this relaxed reasoning, they could patent kitchens, shoes, blood, ring fingers, knees, haircuts or even the ocean and thereby gain exclusive use to them. It has not got quite that silly yet, but similar insanity has already happened in principle.~ Roedy (1948-02-04 age:69)