The cloning industry's latest rationalization.

The cloning industry's latest rationalization.

The cloning industry's latest rationalization.

How you look at things.
Nov. 28 2001 5:52 PM

The Too-Weak Rule

A new line has been drawn in the debate over when life begins. The line is called gastrulation. It takes place about two weeks after conception, when the embryonic mass begins to organize itself into layers, forming the first outline of an organism—or, in the case of twins, two organisms. Advocates of human cloning are drawing this line in order to avoid the abortion debate. Prior to gastrulation, they argue, the developing cluster of human cells can't be a person, since it hasn't clarified whether it will become one organism or two. The argument is clever and attractive. But it's being dissolved by the very technology it's supposed to promote.


Last weekend, Michael West, the CEO of Advanced Cell Technology, announced that his company had created the first cloned human embryo. The purpose, West explained, was to develop cures for diseases. On Meet the Press, West argued that since ACT plans to destroy its cloned embryos before gastrulation, "Scientifically, the entities we're creating are not an individual." On Late Edition, he elaborated:

William Saletan William Saletan

Will Saletan writes about politics, science, technology, and other stuff for Slate. He’s the author of Bearing Right.

We're talking about making human cellular life, not a human life. A human life, we know scientifically, begins upwards, even into two weeks of human development, where this little ball of cells decides, "I'm going to become one person," or "I am going to be two persons." It hasn't yet decided. No cells of the body of any kind exist in this little ball of cells. And that's as far as we believe it's appropriate to go in applying cloning to medicine.

West is trying to solve what he calls the "slippery slope" problem. He wants to erase the moral line pro-lifers have drawn at conception. On the other hand, he wants to assure us that the line can be redrawn nearby. "Almost all views holding that human life begins at conception maintain that this is the moment when a new and unique human individual comes into being," West and his ACT colleagues wrote a year ago in the Journal of the American Medical Association. This isn't true, they argued. "Developmental individuality, which is central to personhood, is not attained until the primitive body axis has begun to form" during gastrulation. Therefore, society can permit destructive research on pre-gastrulation embryos without sliding toward destructive research on more advanced embryos. "The line established by gastrulation and the appearance of the primitive streak is a clear one," West and his collaborators asserted. "It is unlikely that researchers working in properly monitored environments will blur these distinctions."

Too late. The distinctions are already blurred. West agrees with pro-lifers that personhood prior to birth is defined by two things: totipotentiality—the ability to become a whole organism—and the resolution of individuality. He merely disagrees about the moment at which that combination occurs. But in the age of cloning, both standards lose their significance. Every cell is totipotent, and individuality is never resolved.


West succeeds in the destructive half of his philosophical mission, erasing the line at conception. In cloning—somatic cell nuclear transfer—the nucleus of an egg cell is removed and replaced by a nucleus taken from a body cell. The product of this union, when incubated, begins to grow into an organism genetically identical (with the trivial exception of non-nuclear DNA) to the organism from which its nucleus was taken. It lacks the genetic uniqueness by which pro-lifers have traditionally defined personhood.

So pro-lifers turn to the second criterion: totipotentiality. The newly formed entity is a person, they argue, because it has all the ingredients necessary to form a human being. Implant it in a womb, and it will become a baby. But with cloning, this is true of any cell. Put its nucleus in an enucleated egg, implant it, and it will become a baby. Soon, the egg's hosting services may be unnecessary. According to U.S. News & World Report, ACT has filed for a patent on the reverse technique, in which the egg's proteins are injected into the body cell. "Research advances are making all cells 'embryonic,' "ACT Vice President Robert Lanza explained to U.S. News. Consequently, totipotentiality is no longer a meaningful standard of personhood. "To commit ourselves morally to protecting every living cell in the body would be insane," Ronald Green, ACT's chief ethicist, told the magazine.

The reason this breakthrough won't lead to moral chaos, according to West, Lanza, and Green, is that gastrulation establishes a new threshold of individuality. You can kill an embryo at one week, because you don't know how many people it will become. But you can't kill it at three weeks, since at that point the question has been resolved.

Except it hasn't. That's the unintended lesson of ACT's experiment. The donor of the cloned nucleus, a 40-year-old doctor named Judson Somerville, says an Episcopal bishop assured him that the project wouldn't constitute the creation and killing of life, because the clone was simply an extension of himself. "These are my cells being multiplied in a lab, not those of some other human being," Somerville told U.S. News. So, the question that emerged as the clone began to grow wasn't whether it would become one person or two. The question was whether it would become the second Judson Somerville or the second and third. Forty years after the original Somerville "cells" crossed the gastrulation line, we still don't know how many people they'll become. As long as you're shedding cells, the same is true of you. The era of conclusive individuality is over.

The erasure of the moral significance of the gastrulation line doesn't end the debate over cloning. But it does collapse the wall that West and his colleagues tried to erect between the cloning debate and the abortion debate. To justify their research, they'll have to fall back on arguments about the early embryo's incapacity for thoughts, feelings, or experiences. Meanwhile, pro-lifers will have to explain why a newly conceived embryo is precious if neither its genome nor its totipotentiality is unique. All of us will have to figure out how old values, by absorbing new realities, can re-establish moral boundaries along the continuum of life. It's not the end of the world. It's not the beginning, either.