Scientists in the United States say they have created a human embryo through cloning.
The study, published in the journal Cell, used methods like those that produced Dolly the sheep in 1996.
The BBC reports somatic cell nuclear transfer - has been well-known since then.
Now a team at the Oregon Health and Science University has developed an embryo to the blastocyst stage - around 150 cells - which is enough to provide a source of embryonic stem cells.
Skin cells were taken from an adult and the genetic information was placed inside a donor egg which had been stripped of its own DNA. Electricity was used to encourage the egg to develop into an embryo.
