When Chinese and American researchers reported this week that they had used a cutting-edge DNA transfer to impregnate an infertile woman in China, they set off an ethical, political and scientific debate.
The reason: The American scientist turned his technique over to Chinese colleagues because they could try it without waiting for permission from the U.S. Food and Drug Administration.
The announcement touched a nerve in the scientific community. Should a U.S. researcher move experiments overseas to avoid regulations designed to protect human research subjects?
To some, the answer is clear. "I think in this situation, doing research in another country where the regulations are less protective of patients is not ethical. And there have been many situations before where that's been made clear," said Mildred K. Cho, associate director of the Stanford University Center for Biomedical Ethics.
But not everyone is so sure. The debate reflects divisions of thought in a fast-moving medical discipline where scientists are using the building blocks of biology to treat disease, create new human tissues to replace damaged ones and - in this case - spur development of new human life.
Critics argue that the nuclear-transfer technique doctors used to impregnate the Chinese woman was perilously close to human cloning. Others say it's much more like the in vitro fertilization techniques widely used in U.S. clinics.
"This is clearly closer to the way they do traditional infertility treatment," said Jonathan D. Moreno, director of the Center for Biomedical Ethics at the University of Virginia.
Moreno says the FDA might be going too far by requiring anyone who wants to transfer a mother and father's DNA into a donor's egg as part of a fertility treatment to apply to the agency for permission.
Like many ethicists, he sees a future of controversial research popping up in countries with less restrictive policies than the United States because biological and genetic information is easy and cheap to transfer.
Some foreign labs are already paying top dollar to recruit U.S. researchers, and countries that haven't traditionally been seen as research powerhouses now have a growing number of highly trained scientists.
In their experiment, researchers from New York University and Sun Yat-Sen University of Medical Science in Guangzhou, China, took DNA from a prospective mother and father and transferred it into a hollowed-out donor's egg whose own nucleus had been removed.
The reconstructed product was then transferred into the mother's uterus.
She became pregnant with triplets, but none lived - the result of obstetric complications that researchers said were unrelated.
In an abstract of their findings presented to the American Society for Reproductive Medicine, the scientists said they detected no genetic defects or other problems in the fetuses they tested.
Scientists used a similar nucleus-swapping technique in creating Dolly the sheep. But in that case, a sheep's own DNA was fused into a hollowed-out egg before being implanted, creating Dolly, an exact copy.
"There's no fine line there," said Dr. John Gearhart, a developmental biologist with the Johns Hopkins School of Medicine. He said the Chinese fertility treatment was not an example of cloning.
"The procedure is technically the same, but the origin of the nucleus is different. In cloning, you're trying to reproduce an individual that already exists."
But even some who agree with that assessment of the procedure are concerned about the fact that the NYU professor appeared to be dodging U.S. regulations that were designed to protect patients. They note that the reconstructed embryos contained DNA from three people - the mother, father and the donor of the egg.
"We are taking the risk there to introduce third-party DNA, and we don't know, what are the consequences?" said Dr. Jairo E. Garcia, director of the in vitro fertilization program at the Johns Hopkins Fertility Center.
Researcher Jamie Grifo developed the procedure used in the Chinese experiment at NYU and tried it in 1998 on several patients who did not become pregnant.
He told The New York Times that he shared his knowledge with Chinese scientists after the FDA in 2001 began requiring anyone doing such experiments to apply for permission.
The application is similar to the one a pharmaceutical company must file before testing an experimental drug in people, something Grifo said was too time-consuming and expensive, and unlikely to be granted.
"We knew patients would benefit, and we did not want to see the research die," he told the Times.