DUE TO THE controversy regarding destroying embryos for stem cell research, many scientists are studying ways of obtaining cells without harming embryos. I discussed one new finding recently, that stem cell lines can successfully be cultured from a single cell extracted from an embryo, leaving the embryo unharmed. On September 21, an open-access article appeared in the journal Stem Cells reporting a possible new method to obtain embryonic stem cells in a noncontroversial manner.

Embryonic stem cell research is dependent upon in vitro fertilization techniques, and the infertility treatment industry has been the source of a large number of embryos. These embryos are grown in such quantities because IVF and implantation have a high failure rate. Part of the high failure rate is the frequent failure of embryos to grow past the blastocyst stage. The authors obtained 161 embryos donated for research and cultured them. A total of 132 arrested development, 119 in early development and 13 in later development at the 16-24 cell stage. These embryos were observed for 24 to 48 hours to see if any blastomeres would divide. When no division occurred, the embryos were broken up and cultured. From these 13 embryos one stem cell line was obtained.

The cells showed all of the usual markers of stable human embryonic stem cell lines, and appeared to have a normal karyotype. Certainly some abnormality causes division to fail, but not all of the cells in embryos at this stage are typically affected. However, out of the 119 embryos that failed in early development (4-10 cells) not one stem cell line was salvaged. The authors do not comment on this, but I speculate that failure at this stage is probably due to a more integral abnormality that is more likely to effect all of the cells. While the fraction of embryos appropriate for this technique seems to be small, the success rate was not much worse than is often seen with healthy embryos, so it may be practical to pursue this source of embryonic stem cells.

There is debate among scientists whether attempting to find such ways of culturing stem cells in order to avoid ethical concerns is even an appropriate application of science. Certainly we would not say that science should be uninfluenced by ethics–there are entire journals written on the topic of ethics in biological research. I think that the disagreement here is because this is only a grave dilemma in the eyes of a minority of Christians who believe that each embryo (and even each zygote) has a unique soul. This is a problematic statement in more than one way. Such an idea is never stated in the Bible, it is at best implied, and the plastic nature of embryos makes it unclear how such ensoulment could function. For instance, with twinning does one soul become two, and when two embryos merge to form a chimeric individual does one soul die? This problem of ensoulment is neither addressed explicitly in Scriptures nor rationally established by examination of embryonic development. Certainly there are many Christians who do not accept ensoulment at fertilization as dogma. To those who do not believe in souls at all, the whole issue is foolish obstinance about a fanciful notion.

So does that mean that such research is a subversion of science to court a political minority? I think not. Even in the absence of any ethical question curiosity would drive us to find a way to culture embryonic stem cells without embryo destruction, and this process will no doubt teach us about aspects of cell development and differentiation that might otherwise not be known. Additionally, even for those who doubt the existence of souls, there is still an aesthetic objection to the destruction of embryos. While those embryos are not people, they are unique genomes with the capacity to become a person with future development. Probably most of us would prefer a method that allows the harvesting of cells for embryonic stem cell lines while still allowing the source embryo to sample the potential of that genome in growing into an adult.

If we choose to search for a way to harvest cells without destroying embryos, we should do it for these reasons, not to try to satisfy those with dogmatic views on embryonic ensoulment. I think that this is a futile goal. With experimentation we will probably find a way to reverse the differentiation that has occurred by the time stem cells are harvested and render the harvested cells capable of developing into a new embryo, the twin of the parent embryo. People with religious objections to stem cell research are likely to state that this means that all embryonic stem cell research is destroying potential for a new individual and thus inherently unethical. Such people will not be satisfied, and their objections should not govern the actions of the dissenting majority.

Zhang, X., et al. “Derivation of human embryonic stem cells from developing and arrested embryos.” Stem Cells. 2006 Sept 21; [Epub ahead of print]