Many people pay attention to pros and cons of stem cell research and the moral dilemma it poses. It makes you select between two moral principles: you should respect the value of human life; or you should do something to alleviate suffering. It means that if we use stem cell to help prevent suffering, then we are messing with human life. But if no one conducts stem cell research, it would become impossible to alleviate suffering caused by certain diseases such as Parkinson's diseases or birth defects. It's a really hard decision to make.