Why Is There Controversy About Using Embryonic Stem Cells?

The controversy surrounding embryonic stem cell research is similar to that surrounding the arguments about pro choice.  There are those who view conception as the beginning of life.  They believe embryos to be human life.  Therefore, some consider using embryonic stem cells for research as murder in much the same way as those opposed to abortion view that procedure as murder.  Arguments in favor of stem cell research point out that embryos are not viable outside the mother's body.  That's why they have to be frozen.  Human beings can't be frozen, so how can embryos be human beings?  Undoubtedly, the controversy will exist for quite some time.