I don’t think that the Scientific Activist (“Reporting from the Crossroads of Science and Politics”) is at all happy with the “framing” of the reports on the reprogrammed adult stem cells. (beware the language)
However, I did learn where some of the speculation about iPS cells being “like an embryo.” may have come from.
“Activist” says that this article from Jaenisch, et al from last summer indicates that the cells are capable of forming embryos and gestating to become a live, born mouse.
Actually, the article discusses the production of chimeras and the production of a viable embryo after the reprogrammed mouse cells are injected into “tetraploid blastocysts.”
A blastocyst is an embryo. So, the Activist and Art Caplan are pointing to different ways to make chimeras, not cells that are unique individuals with an innate self-driven organization – they are not organisms.
In other words, the reprogrammed cells act like embryonic stem cells, but not like embryos – not like the cell that is a zygote – they can’t make the placenta and direct their own organized embryonic development. The iPS (and embryonic stem cells from the inner cell mass) require more manipulation and the innate organization of another organism, the embryo into which they are implanted.