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Human Cloning

Researchers in South Korea on Thursday announced they succeeded in extracting stem cells from a cloned human embryo. Following a background report on the science behind the research, Margaret Warner and guests discuss the medical and ethical implications of this breakthrough.

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  • SUSAN DENTZER:

    Other scientists have previously cloned small numbers of human embryos that lived for a short time. By contrast, the South Koreans who announced their work today in the journal Science, apparently succeeded on a scale that far outstripped earlier human cloning efforts.

  • HWANG YOON-YOUNG (Translated):

    When we transplant tissues growing from the stem cells into a patient, that patient won't show any signs of rejection by their immune system, therefore, the general science assesses that this technique can offer breakthrough treatments for incurable diseases.

  • SUSAN DENTZER:

    The researchers began with a group of 16 women who were given hormone treatments to produce large numbers of reproductive egg cells. They eventually obtained 242 eggs from the women. Then the scientists used innovative techniques to strip out the nucleus from each of these egg cells. The nucleus is the portion of the cell containing many of the cell's genetic instructions.

    The scientists next took body cells from the same women who had donated the egg cells. The body cells have two sets of chromosomes, the full genetic blueprint needed to create a human being. The scientists then removed these body cells' nuclear material and placed it into the egg cells. The result was 66 cloned eggs, in effect, human embryos, with the exact genetic makeup of the original females.

    Another significant breakthrough followed. The researchers succeeded in growing 30 of the embryos for a week to the so-called blastocyst stage. That's when each embryo consists of several hundred cells. At that stage, many of the embryo's cells are preparing to grow into so-called stem cells.

    Embryonic stem cells are the building-block cells that ultimately develop into almost all the different cells and tissues of the body. The South Korean researchers extracted these primordial cells from the embryos, destroying the embryos in the process. They then grew entire colonies of genetically identical stem cells.

    The South Koreans stressed that their goal was not to create babies that were exact genetic copies of their mothers; that's what's usually referred to as reproductive cloning. Instead, the objective was to create the stem cells, often called therapeutic cloning. The hope is that stem cells could one day be tailor made to match the genetic makeup of a patient suffering from a degenerative disease. If that hope is borne out, stem cell research could lead to revolutionary treatments for a range of diseases from Alzheimer's to Parkinson's to diabetes.

  • MARGARET WARNER:

    Several countries in Europe ban the type of work done by the South Korean scientists. The U.S. has no federal law against cloning human embryos, but President Bush has outlawed it for institutions that fund their stem-cell research with federal grants.

    Now, to explore the medical and ethical implications of the South Koreans' advance, we turn to Dr. John Gearhart, a leading stem cell researcher and professor of medicine at the Johns Hopkins School of Medicine. He's on the board of reviewing editors at Science Magazine, where this new paper was published. And Eric Cohen, a director of the biotechnology program at the Ethics and Public Policy Center here in Washington. He's also a consultant to the President's Council on Bioethics. Welcome to you both. Dr. Gearhart, how big a breakthrough is this scientifically?

  • DR. JOHN GEARHART:

    Margaret, it is a significant breakthrough. What these investigators have done is to demonstrate something which we believe could happen based on the last half a dozen years with cloning other types of embryos. They have demonstrated now that it was possible to do with human embryos. They have taken it a step further. They have taken those cloned human embryos and have been able to extract from them or derive from them these very unique types of cells that are capable in the laboratory of forming every cell type that is present in the human body.

    So now this gives us a very unique opportunity to do several types of experiments for cell based therapies. The first is that we now have an opportunity to get around the immune response, which means that we can now use a patient's own nuclear material to derive stem cells that would match that patient so that any cells grafted to that patient would not be rejected.

    That's very, very significant. We also now have the opportunity to study a myriad of genetic based diseases by generating stem cells that have been derived from nuclear material of patients with those genetic diseases. It is a significant breakthrough. There a lot of work ahead, but we're excited by the results.

  • MARGARET WARNER:

    Would you agree with that, Eric Cohen, that this really is a turning point scientifically?

  • ERIC COHEN:

    It is a very important moment and a very significant breakthrough and I think an ethically troubling one in many ways. Look, we all want medical research to succeed. We all sympathize in a deep way with those sick and who are suffering.

    But this particular area of research creates some real ethical dilemmas. What it involves is the creation of human embryos of nascent human life simply as a research. It creates a class of embryos that we treat really as a mere thing, a thing for our use. The question for the country is whether this is a project that we want to begin. Will this make us a better country and a more civilized country? Or will it coarsen us in a profound way and perhaps weaken our dignity and respect for human life? And I think these are the big ethical questions that we now face. This research and development sets them up for us in a clear way.

  • MARGARET WARNER:

    How do you answer that ethical question, Dr. Gearhart, just the creation of, as Mr. Cohen put it, nascent human life strictly for a sort of utilitarian purpose?

  • DR. JOHN GEARHART:

    I think what we must appreciate is that we take great pride in our country for being a multinational, multiethnic, multi-culture, pluralistic society, and we have very great differences in the interpretations of morally and ethically of what these very early stages of human development represent.

    You have heard expressed by Dr. Cohen — one of those which is that his belief is that a human embryo represents a person at fertilization. But the opinions on this are extremely broad. And so this is part of the dilemma as well. There's a good portion of our society that doesn't hold that opinion and it makes for the debate.

  • MARGARET WARNER:

    Would you say that is still a debatable question? Is this really human life and what is nascent human life?

  • ERIC COHEN:

    It is. It's a deep ethical question. To create embryos outside the body through in vitro fertilization and through cloning creates a kind of mysterious and strange situation — a developing human life — a whole, an organism that's unfolding and how to regard it is a kind of mystery.

    To take that mystery seriously is to act with a certain seriousness and restraint and to begin a process where we are harvesting these embryos en masse, where we're developing them simply as a thing to use albeit for the noble purpose of medical research I think is to cross a boundary this country shouldn't cross.

  • MARGARET WARNER:

    Are you, though, in favor of creating them for in vitro fertilization but not for medical research?

  • ERIC COHEN:

    One of things we have seen and that is troubling is that the moral boundaries have moved. At first we were talking — earlier in stem cell research we were talking about embryos that were left over, that were originally created for reproductive purposes.

  • MARGARET WARNER:

    You mean the ones not used in fertility clinics, not used..

  • ERIC COHEN:

    Exactly, not used and left frozen in fertility clinics. And then we moved to the creation of in vitro fertilization embryos for research purposes, and now we're crossing at another major boundary, which is the creation of cloned human embryos for research.

    And so I think before we proceed down this road and decide if we want to proceed down this road, we need to have a serious public debate and a serious moral debate that takes these questions seriously. And they're not questions that are simply the privilege of people who hold deep religious beliefs; they're questions that I think we can argue about in a rational way and a reasonable way, about what these organisms really are and what we owe them.

  • MARGARET WARNER:

    And then, is part of — at least other critics have said that what also troubles them about this procedure is that those embryos are created for research but then they are essentially destroyed when the stem cells are removed.

  • ERIC COHEN:

    That's exactly right, and this is an area of research that is special in the sense that cloned embryos, nobody wants human reproductive cloning to happen. And so what you've really done is you have created a class of embryos that if we don't want to go down the road toward human reproductive cloning, we have to make them be destroyed. I think that again is a line that we don't want to cross and opens up the other issue, which is whether this really lays the groundwork for the creation of cloned human children.

  • MARGARET WARNER:

    Dr. Gearhart, what is your view of that? I mean first of all the reality that you are then destroying the embryo, but secondly, does this really start us down the slippery slope to reproductive cloning?

  • DR. JOHN GEARHART:

    Well, you have asked me a lot of questions here.

  • MARGARET WARNER:

    Well, go ahead. Take them one at a time. That's fine — separately.

  • DR. JOHN GEARHART:

    The slippery slope argument which is that whatever technology has developed here will aid those who can't to clone human beings is certainly a valid one, which means whatever technology comes out this to derive these early staged embryos could be used if someone wanted to attempt to clone a human being.

    But if we, in our legal end, said you cannot transfer these under any circumstances to a uterus that would take care of, theoretically that issue. And this is what we should be doing. There should be a complete ban on reproductive cloning.

    Now, another issue getting back to what these cells represent, or this early stage — Eric has referred to this as an organism and has used terminology which many other people do not use with respect to what these very early stages of human development represent. Yes, they are human cells. Yes, they are alive, but all of our cells in our body are alive. The issue is, is this embryo a person? And I think that is at the very base of what we're talking about here. In many people's eyes it is not.

  • MARGARET WARNER:

    Let me just ask you one follow up on the reproductive side. What the South Korean researchers did, those embryos, were they in a state that they could have transferred to a woman's uterus and could have been grown into babies? Have they gotten that far?

  • DR. JOHN GEARHART:

    Well, clearly a blastocyst is a stage at which an embryo implants into the uterine wall to continue into the next phases of development. But we know based on a lot of animal studies now that the probability would be extremely high that these embryos would have resulted in abnormal or death to those structures, that there are problems genetically within these embryos that will not permit them to develop, and so this is why we're saying reproductive cloning should not be allowed.

  • MARGARET WARNER:

    Mr. Cohen, if one accepts that the genie is out of the bottle now — I mean, there are countries where this research goes on clearly, is it impossible to come up with some kind of legal structure that would ban one purpose of cloning but permit this other purpose the therapeutic one. I know you don't agree with either, but do you think it is possible to separate the two?

  • ERIC COHEN:

    Sure, I think it is possible. On the issue of the genie being out of the bottle, there are lots of things that other countries do that the United States doesn't do. We're a world leader in biotechnology but we should also be a moral leader in the area of biotechnology. It might be possible to ban reproductive cloning while staying silent about the question of therapeutic or research cloning. That's very legally complicated to do and it's a debate that the country will have and certainly this development I think will spur the debate in Congress but it may be able to write such a law; the two competing bills that we've had in the United States: One bans all human cloning, including both research cloning and reproductive cloning.

  • MARGARET WARNER:

    That's the one the House passed.

  • ERIC COHEN:

    That's the one the House has passed and it's usually called the Brownback Bill. The other bill bans reproductive cloning but explicitly endorses and promotes research cloning. What might be possible is a kind of compromise — is some kind of a way of banning reproductive cloning while staying silent on the question of research cloning. I think this will be the debate we'll have and see if we can break through the stalemate that we have had in the Senate.

  • MARGARET WARNER:

    Dr. Gearhart, what is your view of that as a potential compromise here?

  • DR. JOHN GEARHART:

    Well, again, this is in the political arena and we don't know what kind of bills that will be forthcoming. But I want to point out an illustration here. If we look at the one country that is the closest to us that we view culturally and in every aspect, it's the United Kingdom: England. In England they have laws that permit the use of therapeutic cloning. And this has been a process that has taken about 12 years to get legislation that would enable this to occur. Now this is something which is not out of control. And I would envision that any kind of a program that is put in place in this country and many other countries that you have to have meritorious reasons why would you want to do this. It would be regulated and it would be transparent. We're not going to have this en mass embryo farm that I think the critics of this research are constantly pulling up to us. It won't happen that way and the scientists would support the regulation and oversight in this research.

  • MARGARET WARNER:

    Dr. Gearhart, Eric Cohen, thank you both.

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