3-D printing is one of those protean technologies that few people understand except for maybe the fact that eventually, it will enable anybody to manufacture anything. Anything. So far, 3-D printing has already been used to fabricate spare parts for the International Space Station. And 3-D printing firearm parts and magazines has already entered the national gun control debate. Now, scientists have reported a breakthrough in 3-D printing using human embryonic stem cells that could lead to bioengineered tissue and even artificial organs tailor-made for specific patients. Such a development would revolutionize medicine and how we pay for it. Stay tuned.