Do stem cells always reproduce accurately?

We put this question to Roger Pedersen, from the University of Cambridge.

That's a very good question. If we can culture embryonic stem cells in the Petri dish it looks like if we keep them happy, and give them what they want to be healthy, the answer is yes. They seem to do very well genetically for a long period of time. The thing that makes it intriguing is that possibly our bodies have the same kind of molecular insulation and possibly other tools to make stem cells last longer in a stable and completely normal state.