h EG cells, which originate from the primordial reproductive cells of the developing fetus, have properties similar to those of h ES cells, although there has been less research into their potential.
The third report, an article in the November 12, 1998, edition of the , described work funded by Advanced Cell Technology of Worcester, Massachusetts.
However, there is near universal agreement that the use of NT to produce a child should not now be permitted.
The medical risks are unacceptable, and many people have additional objections concerning the nature of this form of human procreation.
In addition to those research accomplishments, the cloning of Dolly the sheep in 1997 using a technique called somatic cell nuclear transfer or, more simply, nuclear transfer (NT), illustrated another means by which to generate and isolate h ES cells.
h ES cell preparations could potentially be produced by using NT to replace the nucleus of a human oocyte, triggering development, and then isolating h ES cells at the blastocyst stage.
In 1998, scientists reported three separate sets of research findings related to the isolation and potential use of human embryonic stem cells.
Two of the 1998 reports were published by independent teams of scientists that had accomplished the isolation and culture of human embryonic stem cells (hereafter referred to as h ES cells) and human embryonic germ cells (hereafter referred to as h EG cells).
One report described the work of James Thomson and his co-workers at the University of Wisconsin, who derived h ES cells from a human blastocyst, comprising about 200 cells, donated by a couple that had received infertility treatments (Thomson et al., 1998).
Their accomplishment was significant, because h ES cells are considered by many to be the most fundamental and extraordinary of the stem cells; unlike the more differentiated adult stem cells or other cell types, they are pluripotent.