Skepticism Grows over Claimed Benefits of “Therapeutic Cloning”

Date: 07/31/2001

“The idea of therapeutic cloning is falling from favour.” — Nature, April 5, 2001

As Congress prepares to consider a ban on human cloning, some claim that Congress must allow the mass production and destruction of cloned human embryos to produce genetically tailored stem cells for future transplants (called by some “therapeutic cloning”).

However, experts are increasingly skeptical over the claimed “therapeutic” benefits of human cloning. The April 5, 2001 issue of Nature reports that cloning human embryos to harvest their stem cells is being abandoned by many researchers as inefficient, costly, and unnecessary.

“[I]t may come as a surprise that many experts do not now expect therapeutic cloning to have a large clinical impact–many researchers have come to doubt whether therapeutic cloning will ever be efficient enough to be commercially viable. It would be astronomically expensive, says James Thomson of the University of Wisconsin in Madison, who led the team that first isolated E[mbryonic] S[tem] cells from human blastocysts.”

The article continues: “[M]ammalian cloning is inefficient, even in the hands of the most skilled scientists. Of the 277 cells from Dolly’s mother that were fused with donor egg cells, less than 30 developed to the blastocyst stage. At the time experts believed efficiency would improve. But despite feverish efforts by groups worldwide, progress has been disappointing. We don’t at the moment have any real handle on how to greatly increase the efficiency, admits Alan Coleman of PPL Therapuetics near Edinburgh, the company involved in the Dolly experiments.”

Noting the short supply of human eggs, and the expense and inefficiency of cloning, the article concludes that the prospects for therapeutic cloning have “dimmed” and those who still favor it are taking a “minority view.” The article also cites several alternative approaches by which researchers now think they will more effectively produce genetically matched cells for tissue regeneration using embryonic stem cells, adult stem cells, and even patients own engineered body cells. [See Peter Aldhous, “Can they rebuild us?”, Nature, April 5, 2001, pp. 622-5.]

Even on pragmatic grounds, “therapeutic cloning” is wasteful and ineffective. No one should oppose a complete ban on human cloning based on the mistaken view that medical progress depends on protecting so-called therapeutic cloning.