WHEN LIFE BEGINS ISN'T THAT SIMPLE

Recently, David Limbaugh argued life begins at conception and, therefore, research using embryonic stem cells should be banned. This argument rests on two misconceptions.

The first is biological. Life does not begin at conception, at least not in any clear sense.

The conception of a human is the union of an egg and a sperm. These are special cells, containing only one copy each of the genetic information required for a human being, known as the genome. Each is genetically unique. They are unquestionably human, readily distinguished genetically from sperm and eggs of other organisms. They are alive. Both eggs and sperm perform all the complex biochemical functions of typical human cells.

When fertilization occurs, sperm and egg fuse to form a new, genetically unique cell known as a zygote. Life, though, hasn't begun here, as the components that came together were alive to begin with. A new, genetically different individual has begun, but that also happens every time a sperm or egg is produced. Is it then murder to discard a human egg or sperm cell?

This leads to the second misconception, an ethical one. Life, even human life, is not necessarily identical with personhood. Is a sperm or egg a person? I know of nobody who would claim this. Is a zygote a person? Some people hold this view, but it is not obvious. It seems to me a zygote has the potential to become a person. To do so, it must become attached to the wall of the uterus. It must then divide into two cells, then four, then eight, and so on, developing over a period of nine months into a recognizable baby with all the mental, physical and biological activities of a human person. A large proportion of zygotes fail to survive to this point.

How different is the status of a zygote from that of an unfertilized egg? Each is a single, living, genetically unique human cell. Each has the potential to develop into a human being, given a great deal of luck and active support from the mother's body (and from a sperm cell, in the case of the egg). The only distinct difference is that the egg contains one copy of the genome, while the zygote contains two.

Nobody likes gray areas. It's tempting to draw a clear line between person and non-person and locate it at the moment of fertilization. Unfortunately, there's just no biological or biblical justification for doing so.

The ancient Hebrews do not appear to have regarded the fetus as a person. Exodus 21:22-25 stipulates that a man causing a woman to miscarry pays a fine, though harm to the mother is considered more serious. Our current laws and majority attitudes, I think, do a fairly good job of dealing with the lack of a distinct line. We all agree that full personhood is present at birth. During the last trimester of pregnancy, when brain activity is readily detectable in the fetus, we greatly restrict or even prohibit abortion. Prior to that, our laws permit abortion with few restrictions, though most of us still regard it as a serious ethical decision.

Contraceptive methods, such as the IUD which prevents implantation of the zygote in the uterus, are not generally even regarded as equivalent to abortion. Sperm and eggs may be disposed of freely, and few of us worry much about their fate. In effect, society recognizes a spectrum of gradually increasing personhood from conception to birth. If this is the case, then it is entirely appropriate to weigh the ethical choices in embryonic stem-cell research. The work in question would require destruction of human embryos, usually at around the eight-cell stage, and would result in medical benefits to adult humans.

To claim a bright line between life and non-life where none exists is to oversimplify the question. Doing that may cause very real harm to persons whose lives could be saved by the results of embryonic stem-cell research.

Allen Gathman of Pocahontas, Mo., is a biology professor at Southeast Missouri State University.