In the debate over embryonic stem cell research the key principle at issue isvalue of the research or whether cures are imminent or whether the United States is falling behind other countries. The key and determining issue is "When does human life begin?".

Pro-Lifers understand that human life begins at conception (fertilization in the terminology of biology) and we are solidly backed up by science, most notably in the embryology texts used by all doctors and medical schools.

Nevertheless the issue is being continually being argued by some scientists, usually with an agenda requiring opposition to this fact.The following are some of the arguments presented and the counter-arguments for each. Many of these arguments were presented by Dr. Michael Sandel, most recently in an article in the Boston Globe. (www.boston.com/globe/ideas/articles/2007/04/08/embryo_ethics?mode=PF)

The argument for non-humanity are shown in Red. The counter-arguments are in Green.

The embryo is simply a cluster of cells

The embryo is not simply a cluster of cells any more than you or I are simply clusters of cells.  We are all living, multi-cell, organisms of the human species

The embryo in a Petri dish is not growing in a woman's uterus.

That does not make the embryo different or less human than one that is.  Actually the embryo in a Petri dish has a greater right to life since it is not competing against the mother’s rights.

The embryo has no recognizable human features or form.

The embryo is highly recognizable as human by scientists otherwise they would not want the embryo.

Human life develops gradually.

Wrong! Human capabilities develop gradually.  50% alive?  A human is either alive or not.

All living human cells (a skin cell, for example) are "human life" in the sense of being human rather than bovine and living rather than dead.

There is a huge biological difference between a skin cell and an embryo.  An embryo is an internally controlled, multi-cell, functioning organism with all of the information (DNA) and other tools needed to develop itself into a full size adult human. While all body cells have the same information and most are alive and functioning none but the embryo have the tools of a complete organism.

The embryo at the blastocyst stage represents such an early stage of embryonic development that the cells the embryo contains have not yet differentiated, or taken on the properties of particular organs or tissues -- kidneys, muscles, spinal cord, and so on.

The cells have, in fact differentiated.  The outer cells are differentiated to become the placenta.  The inner cells are differentiated to become the fetus, baby, child, adult, maybe even a political philosopher like Dr. Sandel

The stem cells that are extracted from the blastocyst hold the promise of developing, with proper coaxing in the lab, into any kind of cell the researcher wants to study or repair.

The blastocyst,(an embryo) if allowed to continue to live in a woman’s uterus, holds, not just a promise, but a real and functioning capability, without coaxing, of developing into a full size adult person, something that “cluster of cells” already knows how to do and scientists don’t.

Consider an analogy: although every oak tree was once an acorn, it does not follow that acorns are oak trees, or that I should treat the loss of an acorn eaten by a squirrel in my front yard as the same kind of loss as the death of an oak tree felled by a storm.

Despite their developmental continuity, acorns and oak trees differ. So do human embryos and human beings, and in the same way. Just as acorns are potential oaks, human embryos are potential human beings.

Also acorns are not potential oaks. They already are oaks, not maples or hemlocks. Similarly human embryos are already humans, not cows or worms.

Rather than a vegetable species let’s try an analogy closer to our animal species, for example a bald eagle.  It is a Federal crime with severe penalties to kill a bald eagle.  Destroying a bald eagle egg is similarly punishable.  By Federal law a bald eagle egg is a bald eagle at another stage of its life.  A human embryo is a human being at another stage of its life.