When are Stem Cells ok to Use?

I guess I am a little ignorant about the whole moral dilemma of using stem cells. It seems to me that all kinds of great research happens, and there are many positive results that come from the research.

A recent article shows that human stem cells help to repair severed spinal cords in mice. If this can be done, then why all the fuss?

I really believe that something of monumental proportions such as this needs to be considered as morally "good". Two people do not need to conceive a child in order to obtain stem cells, and no one is going to die trying to get them.

I am a Republican, and a Christian. My belief is that fear in this case is stifling a major breakthrough. Religious zealots back in the day didn't want to admit the Earth was round. We forgot most of their names, but we remember Galileo and Aristotle. My final conclusion is when history is recorded, some will have a sinister label and regarded as religiously backward. However; I think people who believe in God should be at the forefront of technology and progress. The Earth, and all living creatures were given to us and entrusted to our care so why not use what we have to it's full potential?