William B. Hurlbut et al., Seeking Consensus: A Clarification and Defense of Altered Nuclear Transfer, HASTINGS CENTER REP., Sept.-Oct. 2006, at 42.
Altered Nuclear Transfer (ANT) is a general concept that might take a variety of specific forms. The basic idea is to employ somatic cell nuclear transfer (SCNT), the technique often known simply as "cloning," but to alter it in such a way that pluripotent stem cells are produced without the creation and destruction of human embryos. In standard SCNT, the nucleus of a differentiated body cell is transferred into an egg cell that has had its own nucleus removed. The egg cytoplasm then reprograms the transferred nucleus and, if all goes as planned, the newly constituted cell proceeds to divide and develop like a naturally conceived embryo.
In ANT, the adult body cell nucleus or the egg cytoplasm or both are altered before the nucleus is transferred into the enucleated egg so that the newly constituted cell will, from the outset, lack the integrated unity and developmental potential of an embryo, yet will nevertheless possess the capacity for a certain limited subset of growth sufficient to produce pluripotent stem cells.
This process mirrors certain naturally occurring phenomena. Recent evidence from infertility studies suggest that, in the natural reproductive process, incomplete or inadequate combinations of the necessary elements lead to many "failures of fertilization." Some of these naturally occurring failures may still proceed along partial trajectories of organic growth without being actual organisms.
Some of these aberrant forms appear to be capable of generating embryonic stem (ES) cells or...