California's $3-billion stem cell program has encountered repeated setbacks since it was approved by voters 17 months ago. Now it faces an entirely new and potentially even more worrisome challenge arising from two powerful patents -- patents No. 5,843,780 and No. 6,200,806, to be exact -- which cover all human embryonic stem cells and the method by which they're made.
Patents are supposed to stimulate innovation. That's why they exist. But it appears that these two patents, held… more