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Cows with human hearts, pigs with human kidneys, sheep with partially human brains - now, this is all still in the distant future, but some scientists want to use new genetic engineering techniques and human stem cells to take the first step and create embryos that are part human, part animal. The National Institutes of Health has held off on funding this kind of work because of the ethical issues it raises. Now NIH wants to lift the moratorium and move ahead. Here's NPR health correspondent Rob Stein. He broke that news today.
ROB STEIN, BYLINE: The first thing people usually ask me is, what? Why would anyone want to make embryos that are part human, part animal? Carrie Wolinetz, a top NIH scientist says there are some really good reasons.
CARRIE WOLINETZ: It's not something that scientists are doing merely because they can. They're doing it because it's critical to really help our understanding of some of the most terrible diseases that are facing real people.
STEIN: Terrible diseases like Alzheimer's, Parkinson's, diabetes. By letting these embryos develop into animals with human cells, tissues or even entire organs, scientists can study them to find new ways to prevent and treat many illnesses. They even hope that someday they could grow fully functioning human hearts, livers, kidneys and other organs in farm animals and save thousands of people who would otherwise die every year waiting for a transplant.
But the NIH knows this can sound very "Frankenstein," so the agency imposed a moratorium on funding any of this stuff about a year ago to figure out what to do.
WOLINETZ: We wanted to make sure before the research moved forward that we were prepared to take into account any special ethical considerations.
STEIN: Like, how human can the animals be without blurring the line between humans and other species too much? Today the NIH announced a plan to lift that moratorium and greenlight these experiments. But there are a bunch of conditions.
Stay away from early embryos of monkeys, chimps and our other close relatives. Never let animals created from these embryos breed if they end up with human sperm and eggs, and make the scientists jump through extra hoops just to make sure they're not doing anything taboo, especially when it comes to making animals with brains that may be starting to become more human.
WOLINETZ: At the end of the day, we want to make sure that this research progresses because it's very important to our understanding of disease. It's important to our mission to improve human health. But we also want to make sure that there's an extra set of eyes on these projects because they do have this special ethical set of concerns associated with them.
STEIN: I talked to several scientists about the NIH's plan, and most of them are thrilled. Irving Weissman is at Stanford University.
IRVING WEISSMAN: If we can find out ways to understand and treat horrible, untreatable human diseases this way, then we should go forward cautiously.
STEIN: But there are critics who say it's just plain wrong. Stuart Newman's a developmental biologist at New York Medical College. He worries this could open up a Pandora's box - pigs with fully human brains, humans with animal brains that would be used for research or body parts. Who knows?
STUART NEWMAN: Science fiction writers might have imagined worlds like this, like "The Island of Doctor Moreau" or "Brave New World" and "Frankenstein." They've been speculations, but now they're becoming more real. And I think that we just can't say, well, if it's possible, then let's do it.
STEIN: The NIH says the new rules are designed to make sure nothing like that ever happens. The general public has 30 days to tell them what it thinks about all this, but the agency hopes to start funding experiments by early next year. Rob Stein, NPR News.
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