DNA engineering can be used to create new drugs, fight disease and create new, sustainable biofuels. But all anyone wants to talk about now are the Neanderthals.

Harvard synthetic biologist George Church made headlines last week when, in a Der Spiegel interview, he spoke at length about the possibility of bringing Neanderthals back from extinction. In his book, "Regenesis," Church said an "extremely adventurous female human" could serve as a surrogate mother to a Neanderthal and that the technology is almost ready to make revitalizing the species a reality.

Church quickly backed off his comments to the German magazine. In an interview with the Boston Herald, he said he's "certainly not advocating [creating Neanderthals]." But some of his colleagues wish he'd move off the topic altogether.

Pete Shanks, of the Center for Genetics and Society, which strongly opposes human (and Neanderthal) cloning, wrote a blog post condemning Church's comments to Der Spiegel and says he's also discussed Neanderthal cloning with the New York Times, the Colbert Report, Science, and Bloomberg Businessweek.

In an interview with U.S. News, Shanks said the suggestion scientists would need a "cohort" of Neanderthals is "irresponsible speculation."

"He appears to be advocating for this kind of use of the technology, but he's doing it in a way that gives him plausible deniability," he says. "He is a currently practicing, really senior scientist. He's not a retired scientist who can say anything he wants. Church is absolutely still doing the work."

Church told U.S. News via E-mail that he would "far prefer to talk about the technology," but that journalists only want to talk about cloning.

"As far as I know, every instanced cited was initiated by a journalist not by me," he writes. "I'm disappointed that [Shanks] feels that a book that 'includes ifs and caveats' and raises social/policy/ethical issues in advance of a crisis is considered 'disingenuous.'"

Still some of Church's fellow synthetic biologists wish he'd focus on the less controversial aspects of the field. Jay Keasling, director of the Synthetic Biology Engineering Research Center at the University of California, Berkeley, says cloning Neanderthals (or humans) is something that may happen far in the future. But for now, he's already reprogrammed bacteria to create substances that can be used to make antimalarial drugs, and he's working on making new biofuels.

"I think as scientists we owe it to the public to be careful about what we talk about. If you give the public the perception that [cloning a Neanderthal] is right around the corner, of course they're going to be up in arms about it," he says. "George [Church] has a great imagination and that's what makes him a fantastic scientist, but the truth is that's a long way off. There's lots of things we can do now that will really benefit people and solve enormous problems, and I think we have to be measured about what we say to the media."

Paul Knoepfler, who studies stem cells at the University of California, Davis School of Medicine, says the Church interview is "pretty detailed and interesting," but that there are a "lot of really complicated ethical issues surrounding the statements."

"To me, it seems very ethically complicated. [Church] suggests he's not advocating it, but you can sense a feeling of enthusiasm, like it'd be cool to do it," he says.

Not all of Church's colleagues agree that his comments are off base. Drew Endy, a biological engineer at Stanford University, says that without outspoken scientists like Church, the public would likely know very little about the field.

"Re-birthing of a Neanderthal might be described as a powerful, attention-getting example of something that should not be done," he writes in an E-mail to U.S. News. "To the extent that George is helping to develop interest among diverse people to learn and participate in what has historically been a technically esoteric but politically difficult topic, his efforts are a basic good of the highest form that should be celebrated."