The purpose of this essay is to stimulate academic discussion about the eth
ical justification of using human primordial stem cells for tissue transpla
ntation, cell replacement, and gene therapy. There are intriguing alternati
ves to using embryos obtained from electives abortions and in vitro fertili
sation to reconstitute damaged or dysfunctional human organs. These include
the expansion and transplantation of latent adult progenitor cells.