For the first time, scientists have created a large batch of cloned embryos from the cells of adult primates, a breakthrough being hailed around the world as the next step towards creating cloned human embryos for research and “therapeutic” applications. Scientists working in Oregon say they have created embryos using the somatic cell nuclear transfer technique from the ova and skin cells of adult rhesus macaque monkeys. They have even succeeded in turning these stem cells into mature heart cells and brain neurons.

The researchers, led by Shoukhrat Mitalipov, a Russian-born scientist at the Oregon National Primate Research Centre in Beaverton, developed a new technique of handling the ova that does not expose them to ultraviolet light or dyes, techniques that have been found to damage primate ova.

The breakthrough marks the first time primate embryos have been cloned in large numbers. Most previous attempts at cloning primates, including humans, have failed or the resulting embryos did not live long and many scientists had thought that cloning primates was virtually impossible.

Although Mitalipov said that he could not comment until the publication of the data in the journal Nature, he did tell colleagues at the International Society for Stem Cell Research in Cairns, Queensland earlier this year that he had obtained stem cells from 20 cloned embryos.

Professor Don Wolf, who led the laboratory at the Oregon National Primate Research Centre, said the team created about 100 cloned embryos. These were transferred into around 50 female macaques, but none has resulted in a full-term pregnancy.

The media have long touted human embryonic stem cell research, including via cloning, as a promise for cures to some of humanity’s most intractable diseases, such as Parkinson’s and Alzheimer’s. Scientists, however, have frequently objected that such claims are more the result of “hype” than actual successful clinical trials. In theory, a cloned human embryo can produce embryonic stem cells that are genetically matched to a patient. From these, many scientists believe tissues or even whole organs could be produced to replace damaged or diseased tissue in the patient that would not be subject to problems with immune system rejection.

Although frequently referred to in the press as “genetically identical,” embryos created by cloning are not exactly the same and attempts at therapeutic application of embryonic cells have resulted in no cures for any disease to date. (Indeed, few have made it to clinical trials.) In addition, some experiments with embryo-derived cells have resulted in wild, erratic and irreversible side effects, including the development of tumours.

Adult stem cells, those taken directly from sources in the patient’s own body, however, continue to yield positive results, including for some of the diseases usually cited as motivation for embryo research.

Other ethicists have pointed out the wholesale production of clones for therapeutic applications would require enormous numbers of human ova, numbers far exceeding what can be made safely available. The procedure for ova extraction can be dangerous and involves drugs and a surgical procedure. Some have warned that the demand for ova created by such promises of cures could only be met by economic exploitation of vulnerable women, particularly in the developing world.

Meanwhile, the United Nations has issued a report titled, “Is Human Reproductive Cloning Inevitable: Future Options for UN Governance,” that suggests it is only a matter of time until human cloning is achieved. The report says 50 countries have outlawed human cloning, while 140 have no ban. These “cloning bans” however, have been heavily criticized by experts who say that the inaccuracies and evasive language used have resulted in few effective prohibitions. While the report calls for a universal ban on human cloning, it continues the widely discredited claim that “human cloning” means allowing a cloned human embryo to be implanted in the womb and brought to term, while at the same time calling for more cloning for “therapeutic” purposes.

A version of this article first appeared Nov. 12 on and is reprinted with permission.