I always enjoy debates with you. Indeed, I was delighted to receive your response to my earlier post, because it illustrates so well the confusion that reigns among many members of the bioethics community when it comes to the use of the term "human life." This term actually has two distinct meanings. It is used to describe conscious individuals with a functioning brain, and it is also used to describe the individual human cells that we scientists can grow in petri dishes. The distinction between these two usages is best exemplified by considering what happens right after someone is shot to death with a bullet to the heart. (Tom--this doesn't mean I support murder.) The person is clearly dead even though 90 percent of the cells in his body are still alive. Indeed, some of the dead man's organs can continue to function if they are transplanted into the bodies of other people! But how do we typically treat those precious forms of human life? We consign them to death by starvation in a coffin or death by incineration through cremation.
My post was directed entirely at the ethics of performing experiments on various kinds of human cells in the laboratory. I never once addressed the ethics of creating people from those cells (which I am happy to debate in another forum).
I will repeat what I said in my first post--what Dolly tells scientists is that there is no metaphysical difference between any living cell with a complete set of human genes. Our current understanding of biochemistry and genetics tells us that they all have the potential to become reprogrammed to start anew the development of a conscious human being. Potential is the key word here. It does not mean that we actually want to do it, it does not mean that we have the technical capability of doing it today, and it does not mean that it will ever be efficient with some cells. But I don't see why different degrees of potentiality (determined simply by the currently available technology) should cause us to view an embryo cell as being ethically different from a cell blown out of my nose.
We should save our respect for human beings, not cells and tissues from embryos and fetuses. The ban on the use of federal funds to perform research on such cells is a testament to the political power of the radical right to impose its religious views on the rest of society at the expense of medical research that could save many conscious human lives.
P.S.: It is important to understand exactly what makes an embryo cell behave differently from a nose-blown cell. Both have the same DNA with the same genetic code. But at the outset they have different proteins loosely attached to different regions of that DNA. The type and location of proteins on the DNA determine the portion of the genetic program that is being run, which, in turn, determines the behavior and "potential" of the cell. At the moment, with our primitive knowledge, we can only blindly reboot the genetic program of an adult cell by fusing it to an unfertilized egg. But once we understand exactly which proteins are involved, it may become possible to simply add those proteins directly to a nose-blown cell to convert it into an embryo. (What Tom Murray and the other members of the National Bioethics Commission seem to be suggesting is that either 1) the positioning of protein molecules on DNA is determinative of whether a human cell is deserving of our respect; or 2) some cells have souls while others do not. Which is it Tom?)