A Step Toward Ex Vivo Gestation?

The biggest news of the week has nothing to do with the U.S. presidential election.  The bigger scoop is that scientists have grown human embryos in the lab for 13 days after fertilization.  The previous record was 9 days.  The work was stopped after 13 days’ maturation because many societies ban research on human embryos that are more than 14 days old, the latest point at which natural twinning can occur and at which, according to the reasoning behind the ban, a unique individual exists.

This work was done on embryos “donated” from an in vitro fertilization (IVF) clinic.  Potential applications include using older human embryos to text the toxicity of new drugs (pushing the dose concentration until toxicity occurs), studying birth defects, trying to understand how to grow stem cells into embryos or something like it, and improving the efficiency of IVF.  In all cases, embryos would be destroyed (that is, killed on purpose) for the sake of research, and if “donated” embryos were not available, then some would have to be created solely for research.  So the embryos are like lab animals, except that PETA wouldn’t get upset.

If, as I hold, human life begins at conception—and the recent “flash of light” observed by Northwestern University researchers at fertilization is provocative, at least—then keeping the embryos alive longer is ethical only if the subsequent intent is to bring them to term.  Turning a human stem cell into a human embryo is an unethical enterprise at its core, as is using the embryos for pharmaceutical toxicology experiments.  If insights into birth defects or IVF efficiency could be gained without killing the embryos on purpose, that could be ethical.

Of course, any ethical concern about such treatment of human embryos will be rejected by the technological community as “politics interfering with science.”  That’s always the charge when an elected official raises life issues. 

And, not surprisingly, the 14-day boundary is now being challenged because it is appearing technically feasible, in the foreseeable future, to keep embryos alive in the lab for longer, and ultimately “lead to scientists being able to study all aspects of human development with unprecedented precision.”  So it goes with any bioethics ban; agreed to only when there is no associated opportunity cost.

I expect that soon the “boundary” will be moved to some point that is deemed politically palatable—perhaps 13 weeks, the end of the first trimester—and will be moved again when that boundary is approached at some undetermined future point.  It could take a while, because beyond 14 days interaction with Mom apparently is critical for future growth.  But it will be tried, because the embryologists, without irony, are embarrassed that they can tell their students more about animal embryology than human embryology.  Also, if the aforementioned stem-cell-to-embryo-like-object work progresses, it will be unclear whether the result is really a human embryo, and therefore subject to the ban.  Maybe someday someone will bring such a construct to term in an attempt to settle the question.

Working back from the other direction, maybe work on an artificial placenta or artificial uterus will facilitate further growth and maturation of embryos outside the human womb. 


So much of this work seems so monstrous on its face, as the logical endpoint at least used to sound monstrous when Huxley wrote of it decades ago, but the point now seems lost.  There is no stopping this.  Leon Kass some time ago fretted that someday some religious conservatives might accept “babies born in bottles as long as no embryo is destroyed in the process,” except many will be destroyed on the way there, and the end result would be the complete replacement of human procreation with production.

Crazy?  I’m not a young man, so maybe I’m just turning into a cranky old one.  Or maybe I’m just putting politics in front of science, instead of quietly capitulating.  The 14-day limit should stay in place.

In the name of God, forbear!

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Steve Phillips
5 years ago

While it is better to have some limit rather than no limit on destructive research on human embryos, the 14 day limit based on the potential for twinning never made much sense. Why would it be more acceptable to experiment on and destroy a human embryo that could become two human embryos than a human embryo that will continue to be one. By that reasoning if human cloning for live birth were feasible no adult human being could be considered a person with full moral status because every adult human being would have the capability of becoming two or more human beings. The connection with twinning has always been a smokescreen to take the focus off the fact that the limitation of human embryo experimentation to 14 days was creating a category of human beings who were required to be killed.

5 years ago

Gestation complicated anemia, hematological system disease and thrombocytopenia could increase the harmful effects on mother and fetus. In cell biology, ex vivo procedures often involve living cells or tissues taken from an organism and cultured in a laboratory apparatus, usually under sterile conditions with no alterations for up to 24 hours.