Should Embryonic Stem Cells be Used for Medical Research?
On Monday 9 March 2009 President Obama signed an executive order reversing the Bush administration's ban on the use of Federal funding for embryonic stem cells for medical research (and presumably for any medical treatments that might eventually be developed as the result of that research). This policy change has raised a storm of controversy among right-to-life- advocates, and also among "intelligent design" supporters. This controversy has centered on the ethics of science, and whether scientists should be allowed to pursue their research wherever it leads.
Currently, most embryonic stem cells are derived from human egg cells that have been fertilized in vitro (that is, outside of the body of the egg-donor mother) as part of the process of in vitro fertilization (IVF) whereby childless couples can conceive of a baby using their own genetic material.
IVF clinics generally fertilize multiple donor eggs and then let them
divide by mitosis until the blastula stage is reached. During this process the inner cell mass is formed inside the blastula, from which embryonic stem cells are derived. The point to this process is not to produce the embryonic stem cells in the inner cell mass, but rather to produce viable blastulas, which can then be implanted in the uterus of the egg donor (or, in rare cases, a surrogate).
The way this process is carried out necessarily produces multiple unused blastula-stage embryos for every one that is implanted. These unused blastula-stage embryos are usually frozen in liquid nitrogen, in case the egg donor requires a repeat implantation.
Currently, there are almost half a million such blastula-stage embryos frozen in liquid nitrogen in IVF clinics in the United States, which leads to the first ethical question:
What becomes of the unused frozen embryos, and who decides?
Here is what generally happens:
Any embryos that you do not use in your first IVF attempt can be frozen for later use. This will save you money if you undergo IVF a second or third time. If you do not want your leftover embryos, you may donate them to another infertile couple, or you and your partner can ask the clinic to destroy the embryos. Both you and your partner must agree before the clinic will destroy or donate your embryos. [source]
So, should the "parents" (i.e. the egg and sperm donors) have the right to decide that their unused blastula-stage embryos be destroyed? Despite some political efforts to deny them this right, there is no legal jurisdiction in the U.S. in which this right has been abrogated (yet).
One way to solve this particular ethic dilemma is to "adopt" the frozen embryos by having them implanted in an "adoptive" mother. There is an organization that advocates this, Nightlight Christian Adoptions, and has arranged for some of these frozen embryos (which the organization calls "snowflakes") to be "adopted" by implantation in "adoptive" mothers who are medically infertile (and married).
According to data at that website, the current number of successful "snowflake adoptions" is approximately 202 since the program was started in 1997. That works out to around 17 per year, or 0.0034% of the current half-million "snowflake backlog". At that rate, all of the frozen embryos currently in cryogenic suspended animation will be "adopted" by the year 31421.
However, this grossly underestimates how long this backlog will persist, as it assumes that no new "snowflakes" are generated by new IVF procedures. Currently, the rate of production of new frozen blastula-stage embryos at IVF clinics in the US is approximately 18,000 per year. The current rate of "snowflake adoption" is approximately 20 per year, so unless IVF is permanently stopped, it is mathematically impossible for the current "snowflake backlog" to eventually be "adopted".
One way to avoid the use of embryonic stem cells taken from frozen blastula-stage human embryos is to use adult stem cells instead. There are many different tissues in adult humans that qualify as pluripotent stem cells (that is, cells that can continue to divide by mitosis). Recent research has made it possible to "regress" adult stem cells almost to the embryonic stem cell stage, which raises the possibility of using adult stem cells instead of embryonic stem cells.
Personally, I strongly hope that adult stem cells can be used for all of the scientific and technical uses that most scientists originally thought only embryonic stem cells could be used for. However, this will then lead to two new, unforseen ethical dilemmas:
What will be done with the "snowflakes" that are currently frozen at IVF clinics, if they are not used for stem cell research and medical treatment?
What will be done with the adult stem cells that have been regressed to the embryonic stem cell stage, since these would then qualify genetically and developmentally as "snowflakes" themselves?
Clearly, one irony of the development of adult stem cell regression will be that the "snowflakes" now frozen in liquid nitrogen in all of those IVF labs will now almost certainly be disposed of (I suppose they defrost and incinerate them), rather than contributing to the advance of medical technology and human welfare.
The other irony, of course, is that by regressing adult stem cells to the embryonic stem cell stage, there would be many more "snowflakes", rather than fewer, thereby necessitating the destruction of many more "potential human beings" than is currently the case.
There are two other solutions, both of which avoid the ethical dilemmas outlined above. One alternative would be:
To consider that neither embryonic stem cells nor adult stem cells are "human beings" until they are implanted into a mother and are born as human babies.
This, of course, would require defining "human life" as beginning at birth, rather than "conception" (regardless of where that "conception" took place).
Another alternative would be:
To consider that all stem cells are "human beings", which would require that all stem cell research and treatment and all forms of in vitro fertilization be declared unethical, and presumably outlawed.But this would also require that we outlaw all developmental research, because somewhere along the line some researcher somewhere might find out how to regress any human cell to the embryonic stem cell stage, and then simply scratching your head or drinking a cup of too-hot coffee would be equivalent to murder.
As always, comments, criticisms, and suggestions are warmly welcomed!