The retirement of Justice Sandra Day O’Connor has electrified the religiously based anti-abortion movement, which hopes to get President Bush to name a replacement who shares its views. In the coming debate, you will hear the argument that science says “life begins at conception,” and that therefore abortion of even the tiniest fertilized ovum, or blastocyst, is murder.

This must be challenged. Life does not begin at conception. Life began billions of years ago and has never stopped, but has just transformed itself into new configurations, branching out into a vast variety of species. Furthermore, sperm and ova are just as much alive as embryos, and they are just as much “human” in that they contain the genetic code of the individual’s respective parents. Yet anti-abortion activists do not go around trying to save the lives of all human ova and sperm. They only talk about the blastocyst that arises at the moment of conception, when it is claimed that a new human life comes into existence.

Some argue that life begins at conception because at that point a diploid (two sets of chromosomes) individual comes into being. But that claim was shaken when “Dolly” the sheep was cloned by Scottish scientists. Many species reproduce by cloning, not sex. In the United States, there are five species of whiptail lizards that are all female clones of their mama (there is no papa). They eat spiders with as much gusto as do related lizards that reproduce the way we do, even though they have only half the chromosomes and no love life.

Nobody is in favor of cloning humans, but suppose some mad scientist did so. The resulting child would likely have the same thoughts and feelings that you and I have. Would the anti-abortion folks consider it ethical to torture or murder the clone-baby, because it is not really human, lacking a second set of chromosomes? Could such a person be dismembered for body parts without grossly violating our ethical sense? Would anybody react other than with horror?

I hope not. My own ethical attitude would be: who cares about how many chromosomes this individual has, she is a sentient being, with human thoughts and feelings, and it is therefore unethical to kill or harm her. Not only that, she has the right to vote and hold public office, and to have freedom of speech and trial by jury. So whether the egg is fertilized or not is of no importance — it is the fact that the individual is a sentient being that gives us an ethical obligation. And a blastocyst is not a sentient being.

Really, the attitude of the anti-abortion forces is not based on genetics but on religious belief about the existence and nature of the soul. Roman Catholic doctrine, and that of other Christian denominations who oppose abortion, is based on the idea that a soul or spirit becomes attached to the sperm and ovum at the moment of conception, not that their chromosomes are pooled. Rhetoric about the chromosomes combining to create a new individual is an attempt to win over people who do not have a strong belief in the theology.

Because the soul is the real issue here, anti-abortion activists can make the otherwise absurd claim that a tiny blastocyst or embryo is exactly the same as a human being, which is like saying that a little acorn is exactly the same thing as an oak tree.

I make a practice of never arguing theology, a field in which I have no expertise. I do note that the theological doctrine of the equivalence of embryos to full-grown human beings is rather new, because, until the microscope was invented in the 17th century, the Christian world did not know there were such things as sperms, let alone chromosomes, and the notion of “conception” was, accordingly, not based on the idea of the joining of a sperm with an ovum, but on the recognition that, somehow, a baby was the product of sex.

Anti-abortion believers have every right to hold and fight for their point of view, but cannot force such a religiously based stance on others, nor claim that they are doing so on the basis of science.

Emile Schepers is a frequent contributor who teaches social sciences at the college level.