Scientists have finally succeeded in using cloning to create human embryonic stem cells, a step toward developing replacement tissue to treat diseases but one that might hasten the day when it will be possible to create cloned babies.
The researchers, at Oregon Health and Science University, took skin cells from a baby with a genetic disease and fused them with donated human eggs to create human embryos that were genetically identical to the 8-month-old. They then extracted stem cells from those embryos.
The embryo-creation technique is essentially the same as that used to create Dolly the sheep and the many cloned animals that followed. In those cases, the embryos were implanted in the wombs of surrogate mothers.
The Oregon researchers, led by Prof Shoukhrat Mitalipov, did not implant their human embryos and said they had no intention of doing so. They say their technique, in any case, would not lead to the birth of a viable baby.
The same technique, tried in monkeys for years, never resulted in the birth of a cloned monkey, they said.
Nonetheless, the fact that scientists were able to get cloned human embryos to survive long enough for stem cell extraction may be seen as a step on the way to human reproductive cloning.
The Conference of Catholic Bishops, for instance, said that the research “will be taken up by those who want to produce cloned children as ‘copies’ of other people.”
Cardinal Sean O’Malley of Boston said human cloning was immoral, even if used for therapeutic purposes, because it “treats human being as products, manufactured to order to suit other people’s wishes.”
The Oregon researchers, who published their paper in the journal Cell, say their goal is what has been called therapeutic cloning: making embryonic stem cells that are genetically identical to a particular patient.
Embryonic stem cells can turn into any type of cell in the body, like muscles or neurons. That raises the hope that one day the cells will be turned into replacement tissue or even replacement organs to treat diseases.
Human embryonic cells are mainly derived from embryos created by fertilisation in fertility clinics.