The work - involving embryos cloned from a rhesus monkey - is a significant development in cloning technology. The primate breakthrough is certain to be seen as powerful evidence that it is now possible to clone a human being. The researchers have predicted that they will achieve the live birth of a non-human primate within months.

The latest results were achieved in America by Professor Don Wolf, of the Oregon Regional Primate Research Center, who is one of the most respected workers in the field.

Cloning cells from embryos is known to be relatively easy, and Wolf has already cloned monkeys from embryonic cells back in 1997. This weekend, however, Wolf said the same technique was working well with somatic cells - the kind that make up the bodies of adult animals. He said: "We have been working with somatic cells and believe that success is just around the corner as the cloned embryos created from them are growing well in vitro."

Wolf was unable to say when the embryos might be implanted into surrogate mothers. The females need to be at exactly the right stage of their oestrous cycles, and this is hard to predict.

Wolf's interest in such work actually has nothing to do with human reproductive cloning. Their aim is to create lines of genetically identical laboratory animals that can be used to test drugs and therapies much more accurately. Additionally, cloning technology holds out the possibility that humans could one day grow replacement tissues for damaged organs.

There are, however, a number of other groups that are intensely interested in using the work done by researchers such as Wolf to clone humans.

One group of researchers led by Dr. Panos Zavos and Dr. Severino Antinori, both fertility specialists, have set up a consortium in an attempt to create the first human clone "within the next few months".

Some researchers say such a venture is fraught with danger since some of the cloned animals appear to be prone to a number of genetic defects that could also affect a human child. However, other scientists such as Professor Jirtle from Duke University claim that primate cloning is intrinsically safer than cloning other mammals due to genetic "imprinting" differences. Indeed, the Rhesus monkeys cloned in 1997 from embryonic cells were (at the last report) physiologically and developmentally healthy and normal.

If human cloning could be proven to be as safe (for the child) as sexual reproduction, where one in 30 children is born with a serious developmental abnormality, this would present a major breakthrough for infertile couples unable to conceive a biologically related child via any other method.

The entire issue centers around the right of the potential parents to conceive a child, set against the right of the child not to be exposed to an unreasonable level of risk of congenital problems.  However, the answer to this question is subjective, with different people in different situations clearly having different perceptions of what is acceptable risk.

Links:

The Reproductive Cloning Network (cloning resources)

Professor Jirtle - "Humans may be easier to clone"

Oregon Regional Primate Research Center (monkey cloning)

Dr. Antinori's fertility clinic (offering human cloning)

Human cloning foundation (pro-human cloning site)