The process is called bioprinting:

2014 could be a landmark year for an amazing medical technology: human organs built by 3D printers.

San Diego biotech firm Organovo promises that its "bioprinting" technology will successfully print a human liver by the end of 2014, the company told Computerworld's Lucas Mearian.

Mearian reports:

Like other forms of 3D printing, bio-printing lays down layer after layer of material -- in this case, live cells -- to form a solid physical entity -- in this case, human tissue. The major stumbling block in creating tissue continues to be manufacturing the vascular system needed to provide it with life-sustaining oxygen and nutrients. ... Organovo, however, said it has overcome that vascular issue to a degree.

The liver won't be suitable to be used as transplants in human beings. But it will be effective for scientific research and drug testing, Mike Renard, Organovo's executive vice president of commercial operations told Mearian.