Adult stem cells can produce a wealth of cell types, Science authors report. This exciting study by a Swedish team shows that, when grown within an embryo, adult neural stem cells can revert to a precursor state that can give rise to lineages of a variety of tissue types. The pluripotentiality of embryonal stem cells has long been recognized, but current ethical concerns have led to a ban on tissue from embryos. This discovery about the open-ended potential of stem cells from adults opens the way to therapeutic advances, such aas growing replacement organs, that do not require embryonic tissue. Of course, neural stem cells are among the most difficult cell types to obtain from living adults, so it would be nice if we discovered similar versatility in other types of adult stem cells.