More bogus spin from the cloning industry.

More bogus spin from the cloning industry.

More bogus spin from the cloning industry.

How you look at things.
Dec. 27 2001 5:17 PM

Everyone's a Twinner

Why the cloning industry's latest lobbying blitz is a snow job.

Three weeks ago, advocates of human therapeutic cloning told a Senate subcommittee that life doesn't begin until two weeks after conception. The senators in charge of the hearing bought this theory as eagerly as the advocates sold it, and for the same reason: It defines away the inconvenient moral problem of using and killing early human embryos. As "Frame Game" has explained before, the theory is sophisticated and attractive but flawed. It justifies cloning on the basis of a scientific assumption that cloning itself has abolished.

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The advocates who testified at the Dec. 4 hearing, Michael West and Ronald Green, are the CEO and chief ethicist, respectively, of Advanced Cell Technology, the company that recently created the first cloned human embryo. ACT is creating embryos not to produce cloned adults but to develop tissues to cure diseases. Its policy is to destroy these embryos within 14 days. According to West and Green, it's OK to use and kill embryos before 14 days, but not afterward. Why? Because at that juncture—alternately known as gastrulation or the formation of the primitive streak—the embryo clarifies whether it will become one person or two.

William Saletan William Saletan

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

The point of drawing a line, West made clear in his testimony, is to assure everyone that therapeutic cloning researchers won't start using and killing more advanced embryos. The logic of drawing the line at the point of developmental individuality, he explained, is that until the embryo becomes a definite individual, it can't be a person.

If the proposition was that we would clone a developing human being, I would [agree] with Sen. Brownback we shouldn't cross that line. We have a line here. It's the primitive streak. … Primitive streak, I think, is an effective line to draw and say that is the beginning of a human being, and prior to primitive streak we should use some other terminology … because this is not an individualized human being.

Green agreed. Clones incubated less than 14 days "are not yet human individuals," he told the senators. "Two lines can be drawn on that same cluster of cells making identical twins. I think this tells us something very significant: There is a line. It's a bright line that nature has given us for the beginnings of a human being."

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The first problem with this argument is that it confuses two different kinds of confusion. As Frame Game put it months ago, the argument is that since the early embryo could become one body or two bodies, maybe it's nobody.

The second problem, as Frame Game tried to explain last month, is that the line of individuation isn't so bright. West and Green assume that the individuation that takes place within the first two weeks—the clarification of the embryonic mass into one or more distinct organisms—is final. Before two weeks, the embryo can become twins; after two weeks, it can't. Since the possibility of twinning in the one-week embryo is what permits you to exploit and destroy it, the only thing that prevents you from exploiting and destroying a three-week embryo—or a five-week or seven-week embryo—is the impossibility of twinning. But in the era of cloning, twinning is always possible.

Suppose that two weeks ago, West had created a cloned embryo using the nucleus from one of your skin cells. Today, that embryo is beginning to form a single primitive streak. According to West and Green, we now know that the DNA in that embryo won't form a genetically identical second organism. But they're overlooking something: you. You're the first organism formed by that DNA. The clone is a genetically identical second organism.

What West and Green have done is the scientific equivalent of selling you a car on which they've rolled back the odometer. They talk about the clone's DNA as if it's just now crossing the two-week threshold. In fact, the clone's DNA crossed that threshold two weeks after you were conceived. That's the point at which, according to West's theory, the embryonic mass that became you should no longer have been able to form more than one genetically identical organism. By cloning you—growing one of your cells into your twin—West has proved himself wrong. If it's OK to kill a human organism that can still twin, it's OK to kill you right now.

A month ago, when Frame Game first pointed out this flaw, several readers wrote in to Slate's "Fray" to disagree. Developmental individuality involves more than genes, they argued. Your clone will be a different individual from you because it will develop in an environment different from the one in which you developed. That's true. But it's just as true when your clone is one week past creation as when it's three weeks past creation.

The difference between the one-week clone and the three-week clone isn't that one is developing differently from you and the other isn't. The difference, according to West and Green, is that the one-week clone can divide to form two individuals—each of which will develop differently from the same genetic material—and the three-week clone can't. That's what West and Green mean when they say that a three-week clone has attained developmental individuality. And that's what is no longer true, thanks to their work. It can't have been true of you when you were a three-week embryo, because it isn't even true of you today.

West and Green understand that cloning is pulling the biological rug out from under the pro-life lobby. What they don't understand, or won't admit, is that they're standing on the same rug. "In an era of cloning technology, every single cell in our body has the potential to be equated with these [embryonic] clusters of cells," Green told the senators. "It has a similar potentiality to go on to further development in time. So the problem here is that all of our terms, all of our ways of thinking, have been scrambled, really, by technological and scientific data." Green was talking about his opponents' theory of when life begins. He could just as well have been talking about his own.