Last week’s announcement that scientists successfully derived stem cell lines from unfertilized eggs using a process called parthenogenesis has given more fuel to the misguided rhetoric of a radical minority rallying against embryonic stem cell research.
This breakthrough technology has great potential, but also some serious limitations that make it not viable as a replacement for embryonic stem cell research. First, parthenogenesis creates embryos that are genetically unstable. In the natural process, an egg is fertilized by sperm, which creates an embryo with one set of genes from an egg and the other set of genes from a sperm. But embryos created through the process of parthenogenesis have two sets of genes from the egg only. This different combination of genes could lead to abnormal cell development or cancer and increases the risk of duplicate mutant genes that could cause additional health problems.
Stem cell lines derived from this new kind of embryo will also only work for women. One of the goals of stem cell research is to create treatments and tissues that are genetically identical to the patient, thus reducing the risk of immune rejection. Stem cell lines derived from parthenogenetic embryos will only be genetically identical to the woman who donated the egg. And attempts to develop embryos from sperm have not been successful.
This research is a long way away from treatments and cures. Scientists need time to develop means of efficiently isolating and manipulating these new types of stem cells. Stem cells derived from regular embryos, on the other hand, have shown great medical potential today. Scientists have already manipulated these stem cells to treat laboratory animals and create human cells, all of which could lead to life-saving cures.
Furthermore, this new process of creating embryos may not get around ethical objections from opponents of the research. These parthenogenetic embryos have not been created from both a sperm and an egg and are genetically unstable, but, for some opponents they are still human embryos. Those who object to embryonic stem cell research will see this process as creating potential human life for the purpose of research rather than as an alternative source to regular embryos.
Stem cells continue to show extraordinary medical potential. Embryonic stem cells in particular have been used to treat paralysis, vision loss, and Parkinson’s disease in laboratory animals and have created cells that could lead to cures for heart disease, AIDS, and diabetes. The new discovery of a way to derive stem cells from an unfertilized egg also has great potential. Yet new technologies can and should not be seen as substitutes for embryonic stem cell research.