Time to Put Research Cloning on the Back Burner

[Cross-posted from "What's New in Life Science Research" at ScienceBlogs]

I agree with Mike's first point: By now - more than 12 years since the birth of the first cloned mammal, and 10 years since stem cells were first extracted from human embryos - most people understand the difference between cloning for reproduction and cloning for research purposes.

But I think his suggestion that people are wary of SCNT because creating replacement organs seems like magic is way off base. There is a lot of magical thinking going on about SCNT, but most of it has originated with advocates of cloning-based stem cell research who have irresponsibly hyped SCNT as an imminent miracle cure.

In fact, there's been very little progress in cloning-based stem cell research in more than a decade. And even if its considerable technical and logistical challenges were ever overcome, SCNT would be an ethically problematic approach to regenerative medicine - for several reasons that have nothing to do with the moral status of human embryos.

Over the past year, some of the world's top cloning scientists - including Ian Wilmut of Dolly-the-cloned-sheep fame - have announced that they're abandoning their SCNT work. The scientific and medical justifications for SCNT are getting weaker, and the social and ethical problems it raises aren't going away. It's time to put SCNT on the back burner.

Here's why.

It's worth stressing - since so many news stories (not to mention blog posts) are misleading on this point - that SCNT has produced not one human stem cell. And work on it is a very small part of the stem cell world: Only a small number of labs remain interested in trying it, and that number has diminished over the past year as work with cell reprogramming techniques has advanced.

Cell reprogramming looks likely to achieve the very thing that made SCNT so hypothetically compelling: disease-specific and patient-specific stem cells that can do all the tricks "ordinary" embryonic stem cells can do. It raises other concerns, but at least it uses ordinary body cells instead of embryos and eggs.

The scenario in which research cloning would produce "personal repair kits" for each of us was always extraordinarily unlikely. By their nature, SCNT-based treatments would be so expensive that they'd constitute a kind of "designer medicine," out of reach except for the extremely wealthy.

Is it possible that SCNT, along with cell reprogramming, could still be useful as a research tool for studying early disease development or testing drugs? Yes, but SCNT poses other problems.

The Ethics of Eggs

Here's a big one: SCNT requires very large numbers of human eggs. And procuring eggs is an invasive and time-consuming process that puts women at risk of adverse reactions, some of which can be quite serious, even life-threatening.

Remember Hwang Woo-suk, the Korean cloning scientist whose published claims of producing stem cells with SCNT turned out to be fraudulent? Hwang also lied about having found a way to reduce the number of eggs required for SCNT. When a real count was made, it turned out that he'd used over 2200 eggs collected from 119 women. He'd neglected to properly inform many of them about the risks. He'd coerced some of them - including junior researchers in his own lab - to have their eggs extracted. And in violation of Korean law, he'd paid more than half of them - several said they'd agreed because they desperately needed money. Twenty percent of the women whose eggs he'd used experienced serious adverse reactions, and 16 were hospitalized.

The prospect of an increased demand for eggs raised concerns early on about exploiting economically vulnerable women - and that was before the current economic collapse. That's why a number of countries (including Canada, France, China), states (including California), and scientific bodies (including the National Academies of Sciences) have ruled or recommended that women who provide eggs for cloning-based research be reimbursed for their expenses, but not paid more than that.

But the U.S. still doesn't have a federal law that limits payments or establishes other rules to protect women who provide eggs for SCNT research. For that matter, the U.S. - unlike dozens of other countries, including all of those in which SCNT research is known to be taking place - still hasn't passed a law against reproductive cloning.

For these reasons and more, I think it's both too early and too late to continue SCNT research: too early because the regulations that would be required to ensure it could be done responsibly aren't in place, and too late because SCNT is an idea whose time has passed.