On June 13, 2013, the Supreme Court placed its imprimatur on a principle that has been gathering force within patent law for several decades: human beings constitute unpatentable subject matter. In Association for Molecular Pathology v. Myriad Genetics, Inc., the court answered the question it had posed itself–“Are human genes patentable?”–decisively in the negative. This legal result was predictable, given a careful reading of the entrails of judicial decisions, congressional bills, executive branch pronouncements, and decisions in other countries about patents claiming human-related inventions, all of which have echoed the spirit of the Thirteenth Amendment by proscribing property rights-including intellectual property rights-in human beings. To understand how patent law has evolved toward this result, one may trace the legal treatment of patents claiming human embryonic stem cells, chemical products of human physiology, human thought, and now, human genes. Woven together, these strands of evidence led inexorably toward the ultimate rejection of human gene patents by the Supreme Court.