I have to admit, when I first saw that mouse with an ear on its back, I was more than a little freaked out. I mean, to watch tissues grow outside of the body has got to be quite a spectacle. But passed the freaky appearance, there was some really hard work backing all of this up. Considering what these people had to do to get the tissues to grow the right way, they had their hands full. For example, growing tissues in a simulated weightless environment was genius. I never would have guessed to cultivate cells in a rotating bioreactor to put them in simulated free fall. That's some pretty good thinking. They also had to closely mimic the environment in which those cells would normally grow in the human body. You can't tell me that it wouldn't be arduous to unlock biochemical signals to get cells to grow and multiply. In my opinion, these researchers should be commended for their work.
http://www.pbs.org/saf/1107/features/body.htm
http://www.pbs.org/saf/1107/features/body.htm