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Zavos Says Cloning More Efficient Than IVF

Aired August 07, 2001 - 13:31   ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
KELLEY: Once again as we continue to watch the conference on cloning, Dr. Zavos still speaking on the history of cloning right now at the National Academy of Sciences. And Andrew Goldstein and Elizabeth Cohen both still with us.

Andrew, your "TIME" report -- as you listen to this are you hearing some of the science that you were able to report on and look at for the report?

ANDREW GOLDSTEIN, "TIME" MAGAZINE: Yes, absolutely. And it's important to understand why cloning might be a better option for couples than regular in vitro fertilization. Cloning will allow the father to actually have his own DNA in the child, in a way that right now if your sperm is defective, the in vitro fertilization process for you would not have your genetics in that baby.

But on the other hand, it's also important to realize that a lot of ethicists say once you support in vitro it's very hard not to support cloning, because both processes require destroying large numbers of embryos.

KELLEY: And I think we'd have to look at the success rate, too, of what in vitro has done at this point, and don't know what cloning will be there for those risks. Let's get back in and listen to Dr. Zavos. He's talking about Dolly the sheep and some cloning there.

PANOS ZAVOS, ANDROLOGY INSTITUTE: ... that's very important. In the humans we do know exactly how many embryos we should transfer to get a pregnancy and preferably a normal pregnancy. Next slide, please.

A number of studies have already demonstrated -- far higher rates, although -- the groups that -- have published heavily so far. They alluded to the fact that there is a great deal of deficiency and the statistics can't really up to. Several of the scientists that spoke this morning, I think they have alluded to the fact that a great deal of success has been accomplished. Now, there's more to be done, but when you get 30 and 40 and 50 and 80 percent, that, I call success. Because today in human IVF, you get only 30 percent success and you are happy if you do that. Therefore that is what we call success in the assisted reproductive technologies with human reproduction.

Next slide, please. Again, animal cloning efficiency is very low, according to Dr. Wilmut and Dr. Jaenisch, published in "TIME" magazine this year. But although we feel like while the number of cytoplasts utilizes was relatively high, what reason is there to think that this will always remain so? And I think the scientist doing the next-to-the-last session this morning answered that question very, very vividly.

Next slide, please. Now, there is evidence of that. Embryos created, 141 by a group in China, via serial cloning, here. This is the recloning process. Out of that, 45 live births occurred and the success rate is 32 percent. Again, I remind you that human IVF today in the U.S. gets 30 percent success. This is 32 percent success rate.

The next slide, please. Here's a group in Japan. The numbers may not stack up as much, but most of the animal cloners do talk very seriously when they have 10 animals or so because they'll simply be regarded as very clear evidence. Therefore, embryos created: 10, live births: 8. The success rate by Doctor Kato (ph) in Japan is 80 percent. Now, like we say in Kentucky, "This ain't hay." This is 80 percent.

Next slide, please. Now, some of the difficulties noted by animal cloners is poor cloning response, poor implantation and pregnancy ratio and poor health of the animals born. Now, let's go to the next slide, please. Those difficulties are due to poorly designed experiments, poorly executed experiments, poorly approached experiments, poorly understood and interpreted experiments. And I had to say that, but some of them were done for fame and fortune.

(LAUGHTER)

ZAVOS: Next slide, please. The problems lie in the areas of: tissue culture cells used in SCNT and -- I think the scientists addressed this this morning -- improper protection or unprogrammed cell lines, improper understanding of the reprogramming of the genes after the SCNT. Complete lack of embryo screening of the cloned embryos prior to embryo transfer, developmental asynchrony between transfer embryos and uterine environment and persistent use of highly- inbred animal that are susceptible to genetic aberrations during SCNT. And I think that those are very, very direct target areas that I think that we in the human and the animal reproductive arena need to address in order for us to begin to address and perfect those technologies.

Next slide, please. Next slide. OK. I want to address a paper that was recently published by Dr. Wilmut and Jaenisch in "TIME" as well. SCNT is not copying, although they do say that they're copying, because we're simply -- we do not copy someone when we clone someone. And I do realize that when they talk about their animals that they clone, they do not use the term "copying." But when they say something about human reproductive cloning, they're talking about "copying." Why? Because they simply want to -- they want to confuse the issues. And this is really very, very important that we should not be confusing the issues, but rather directing those issues, and make the public aware of the fact that we're not perfect but we're trying to get there as perfectly as we can.

Next slide, please. KELLEY: Dr. Zavos at the conference there in Washington, talking about the success rate and how it looks for human in vitro fertilization, which is about 30 percent, he said, and the animal cloning inefficiency. But he cited some reasons why it is and we'll talk about that a little bit more when we come back.

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