Australian cloning experts acknowledge that problems sometimes arise with animal cloning and that these can result in growth abnormalities or death. But that did not mean cloning should be abandoned, they said. Before Dolly's debut in 1997, scientists thought mammals could not be cloned. But now they have cloned not only sheep but mice, cows, pigs and goats. Given this success, two infertility specialists, Dr Panayiotis Zavos and Dr Severino Antinori, have announced that they intend to clone humans.
Australian scientists are strictly opposed to such cloning, believing it to be morally indefensible.
Peter Mountford, chief executive of Melbourne biotechnology company Stem Cell Sciences, said that given the doctors' aim it was not surprising that scientists were now acknowledging problems with reproductive cloning. However, Dr Mountford is convinced that therapeutic cloning, which involves growing tissue for patients that is genetically identical to their own, could benefit human health immensely. In reproductive cloning, scientists put a cell from an adult into an egg with its genetic material removed. The egg then reprograms the adult cell's genes so that they are ready to direct the development of an embryo, then a foetus, then a newborn that is genetically identical to the adult whose cell was used to start the process. No one knows how the egg reprograms an adult cell's genes, but scientists believe this may be the source of the cloning errors that can occur.