美国国家公共电台 NPR The Chimera Quandary: Is It Ethical To Create Hybrid Embryos?（在线收听）

The Chimera Quandary: Is It Ethical To Create Hybrid Embryos?

RAY SUAREZ, HOST:

Now it's time for our regular feature Words You'll Hear, where we try to understand what's happening in the news by parsing some of the words associated with it. This week, the word is chimera. Yes, it's the mythical being - a lion crossed with a goat and snakes - but it's in the news because it's also the name for a kind of research in which human stem cells are combined with the tissues of other animals with the potential for creating human-animal hybrids.

The National Institutes of Health just lifted a ban on federal funding for this type of research, which has some bioethicists concerned. To break it all down, we reached Insoo Hyun. He's a professor of bioethics and philosophy at Case Western Reserve University. Professor, thanks for joining us.

INSOO HYUN: Great to be here.

SUAREZ: Why are some ethicists so concerned about this? Walk us through the main ethical argument.

HYUN: Right. The main argument in favor of this type of research is that it could be an incredibly useful tool, as it has been for decades in other areas of biomedicine. When you mix human cells and the animal models, you can do many, many kinds of experiments where you can study how human systems behave in an animal before you move on to work with patients and human subjects.

But on the con side, you do have concerns by many people who are worried about the level of mixing that could occur when you use stem cells in your animal models. And one of the concerns might be about animal welfare. We don't know exactly what effect in terms of the animal suffering these experiments will result in.

There's also great concern about the level of human-animal mixing that might result in animals that are not 100 percent animal and not 100 percent human. We may be flirting with an area of human dignity that we just do not want to cross even if the scientific value of the work may be quite high.

SUAREZ: Well, give us some examples of the things that have already been done and what we've been able to find out as scientific research proceeds.

HYUN: Well, one experiment that happened recently was when researchers put human glial cells, which are a type of human brain cell, into mice that did not have the ability to make their own glial cells. When they did this experiment where these mice had large numbers of human glial cells in their brains, they found that the mice were able to solve maze tests twice as fast as normal mice and had memory tests that were twice as fast. So that's an area that in recent years has drawn some attention and could be sort of a harbinger for the kinds of concerns people have as you go outside of rodents and go to more complex, more human-like animals.

SUAREZ: Because we're getting down to a level of combining cells to create something that would never exist in nature, is it different from, for instance, growing human organs inside a pig?

HYUN: I think that is the root of many people's concerns, just this idea of creating something completely new and, in some people's view, completely unpredictable.

SUAREZ: One of the big political divides in the United States has been between Democrats and Republicans over the right to abortion. And some pro-life Americans say they want to stop abortions because they believe even at the earliest stages after fertilization, the resulting embryo is a full-fledged person with a consciousness and with a right to life and a right to be legally recognized as having a right to life. Is this the same ethical debate?

HYUN: If you are creating ambiguous embryos with human cells that are very early in development into an animal embryo, then it does raise the question of what is the moral status of that embryo. Is it an animal embryo and we can just treat it like any kind of lab animal, or is that a human embryo? Or is it something in between? So I think we have a continuum of belief as to what it means to be a human. Not everybody agrees. But this is definitely butting up against that continuum because we are talking about embryo research and human cells.

SUAREZ: You know, I'm thinking back to when in vitro fertilization was first introduced. There were people with a lot of ethical concerns. And we built in guidelines, we still continued to hash it out, and now it's a widely accepted practice. Is this going to be different or kind of like IVF?

HYUN: That's an excellent example. My prediction is that it will be kind of like IVF if we find that there are good medical benefits that come from this activity. So IVF, as you pointed out, was extremely controversial when it was first proposed in the early '70s, mid-'70s. But it wasn't until the inventors of IVF brought out a healthy baby on TV that people clamored for this technology and haven't stopped science.

On the other side, though, what we did find with IVF is with the new technology, you do open up the door for new future controversies. So for example, without IVF, without the ability to grow embryos outside the womb, you would not have had stem cell research.

If chimera research proceeds and if it shows social value, it could open the door for other future technologies that we can't imagine at this time that might themselves generate controversy.

SUAREZ: The word you'll hear is chimera. That's Insoo Hyun, a professor of bioethics and philosophy at Case Western Reserve University in Cleveland, Ohio. Thanks a lot, professor.

HYUN: Thank you.