Looks like one more step to growing your own replacement parts has been made:

Scientists say they have made a significant step towards making human lungs for transplantation.

The UK team at Imperial College London took human embryonic stem cells and encouraged them to grow into cells found in adult lungs.

These lung cells are the type needed to allow oxygen to cross into the blood.

Eventually, it may be possible to make them from other stem cell sources such as bone marrow, the team told Tissue Engineering.

It's often said the discoveries of one century come to dominate the next. The ones I can see so far are buckminsterfullerene (carbon nanotubes) and stem cells. I think it's really exciting to try and pick out what might be next.