A new embryonic stem cell therapy for treating degenerative eye diseases has been deemed safe and effective during animal trials and will begin human trials in the next several months.  This represents the second embryonic stem cell therapy to reach human trials.  As it turns out, there are some fairly significant issues that come with stem cell therapies, at least at this point.  One of the risks associated with stem cell therapies is the resulting propensity for tumor growth.  The other is the