Experimentation on nonviable human embryos

Nature News recently reported that a second Chinese research team has done research on non-viable triploid human embryos in which they used CRISPR-Cas9 genome editing to introduce a mutation that cripples the immune cell gene CCR5 and would make individuals with the mutation resistant to HIV. This research raises a multitude of ethical concerns. Should we be pursuing such research when we have not decided whether using these techniques to create individuals who would be brought to birth would be permissible? Does the fact that only 4 of 26 human embryos targeted were modified and that those were not modified on all of their chromosomes and there were a large number of unintended mutations indicate we are nowhere near ready to try this technique on human embryos? If this could be done effectively would we want to make children with an impaired immune system, but who are resistant to HIV?

I would like to focus on a more basic ethical concern. The researchers in this and the prior Chines study reported in April 2105 justified experimenting on human embryos by using embryos that were non-viable. They obtained from a fertility clinic early human embryos that were triploid, meaning they came from eggs that were fertilized by two sperm and contain 69 chromosomes rather than the normal 46. This is a fatal condition. Most naturally occurring triploid fetuses miscarry in the first trimester and the very few who survive until birth seldom live more than a few days after birth. Embryos created during IVF that are identified as being triploid are not implanted since those doing IVF desire a healthy child, not a disabled one. The researchers contend that the fact that these embryos will not survive makes it permissible to use them for genetic research because it removes the concern that a genetically modified human being could be born.

However, does the fact that a human embryo is destined (almost always) to die prior to birth mean that it is permissible to use that embryo as a research subject? If a human embryo is a human being who has been made in the image of God, then the life that the embryo is living has value and should be respected even if that individual will never be born. When we do research on children who are not able to voluntarily consent to being research subjects we restrict that to research that either has minimal risk to the subject or is being done to try to benefit a child for whom no other treatment is available. Embryos are not able to consent to be research subjects, yet this research is being done on them with great risk to the life that they do have and with no intent to benefit them. If these two sets of researchers do not believe that human embryos deserve this type of respect, then why not use normal embryos instead of triploid ones? In both cases they would be experimenting on living human beings who are incapable of consent and are being killed and the end of the research. Why would it be more acceptable to do that with human beings who are more disabled and have a shorter life expectancy?

We have made significant ethical advances over the past century in our understanding of how we should conduct human subject research. We need to remember that human embryos are human subjects when they are used in research.

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John Kilner
John Kilner
5 years ago

Thanks, Steve, for helping people understand what consistent regard for the dignity of embryonic human beings entails. As you know, U.S. society has previously addressed analogous situations involving other human beings. The question has been: Does the highly likely fact that someone will die soon justify killing him or her earlier to benefit others medically (e.g., by taking his or her organs)? The answer–both regarding dying patients and prisoners on death row–has been: no.

Jon Holmlund
Jon Holmlund
5 years ago

If memory serves, at the CBHD conference in 2015, Maureen Condic said (in discussion in a breakout session) that some of these embryos can survive to term–albeit rarely. If so, just how non-viable is “non-viable?”

Also, my read is that enthusiasts such as Dr. Church at Harvard see the techniques as much further developed than in this case, so the Chinese are behind the curve. So it could be argued that we might be closer to “trying this for real” than is appreciated. That of course does not excuse the creation of humans–likely quite a few, before all is said and done–solely in the name of process development. But it may make the attempts more permissible in the eyes of some.

Then, of course, the goals of the research are also open to question, Steve, as you point out. Is it really a good idea, generally, to knock out CCR5? Where is this leading?

But of course your key point is that embryonic human life merits all the protections we ordinarily afford human subjects, something not currently in the scope of the regulations (45 CFR 46). Dr. Condic challenged us to change that–my guess is that it would take a new statute (i.e., act of Congress, not just new regulations).