Stem Cell Rx No Longer For Sale on Google

Perhaps once a week, I will be asked by a patient about the potential benefits of stem cells for reversing the normal affects of age, particularly with respect to arthritis of the knee joints, hip joints or the degenerative discs in the lumbar spine. I believe one of the reasons for this interest has come from increasing advertisements by various clinics in my region of East Tennessee claiming stem cells are the answer for these problems. My region is not unique. A simple Google search on “stem cells for knee pain” yields ads for clinics offering such treatment.

Stem cells are cells that have potential to become any type of cell in the human body such as a new blood cell, nerve cell or bone/cartilage cell. Scientists are rapidly learning how to find or create stem cells, as well as how to safely use them to replace old or missing cells, thus restoring function in worn out, damaged or diseased areas of the body. In fact, stem cells are presently used to replace the bone marrow for some individuals with certain cancers and disorders of the blood and immune system, and in many of these cases, the results are lifesaving.

The problem is that stem cell treatment remains yet unproven in all other medical conditions, including the age-related arthritis conditions which I treat. This lack of efficacy has not stopped clinics from offering and patients from receiving stem cell injections with the hope of achieving improved function or cure. I am willing to grant that many offer these treatments with the sincere hope and belief that they are acting in their patient’s best interest, though I suspect not all have the patient’s best interest in mind. Unfortunately, there have been severe adverse events. Examples include blindness following an injection of stem cells into the eye, and loss of function with development of a spinal cord tumor following stem cell injection into the spine.

The FDA is trying to educate the public and prevent stem cells from being offered for unproven treatments. The FDA has the authority in the US to stop these unproven treatments and take punitive action if needed. This is not to suggest that the FDA is in the business of preventing legitimate investigation into the potential benefits of stem cells, such as this Mayo Clinic Phase 1 study looking at the risks of injecting stem cells in to the cerebrospinal fluid of patients following a spinal cord injury to see if this particular stem cell technique causes harm (with future studies needed to determine benefit).

The FDA is recently getting some help from Google. On September 6th, Google announced it would stop accepting ads for unproven medical treatments, including stem cell therapies. It is early in the effort and the initial link above still has four ads for non-bone marrow stem cell treatments returned with the Google search. Maybe by the time you read this blog entry, the stem cell ads for unproven treatments will be gone.

I am hopeful that stem cells will eventually provide patients with safe therapies that repair injury and return patients to normal health. Offering that promise without the studies that prove such benefit is unethical and potentially harmful. It is good to see Google favoring human welfare over financial profit.

Two developments

A new effort at “somatic” gene editing in China is reported this week.  The key summary:

“As the researchers report in the New England Journal of Medicine,

[note to reader: subscription required]

they transplanted [blood stem] cells that had undergone CRISPR-based editing [of a gene that encodes for a receptor, or “docking station”] into a patient with HIV and acute lymphoblastic leukemia. While [the edited cells lasted for a long time in the bloodstream of the HIV-infected recipient], they only made up between 5 percent and 8 percent of blood cells. A higher percentage is needed for this to be an HIV cure…”

In “somatic” gene editing, mature cells, such as “adult stem cells” or diseased tissues, are gene edited for the purples of treating a fully-formed individual with a disease.  That is what appears to be in view here.  Similar efforts are in progress to treat sickle cell anemia and other genetic diseases.  The ethical issues are relatively well-understood, and fit within the regime of regulating cells-as-medicines in clinical trials of humans, under the ethical and regulatory regime that governs the latter.

That’s in contrast to “heritable” gene editing, which attempts to edit genes in embryos, fertilized eggs (zygotes), or gametes (sperm or eggs) with changes that would be passed on through the generations, as recent entries on this blog have been addressing.  The Chinese twin girls who were reported to have undergone gene editing late in 2018 are examples of an attempt at “heritable” gene editing.

A second report from Nature describes efforts to use human “reprogrammed” stem cells, aka pluripotent stem cells, to make human “embryo-like structures.”  This is distinct from making a human embryo, for example in IVF, then removing cells, likely destroying it, for use in research or to develop medical treatments.  In conservative commentaries in recent years, these “reprogrammed” stem cells are considered the “ethical embryonic stem cells,” because they can’t form a full individual and they don’t require creation and destruction of an embryo, that would under normal circumstances form a full individual.

Thing is, these “embryo-like structures” can still form something called a “primitive streak,” which, in normal embryos, is the first sign of formation of a nervous system.  The primitive streak usually forms 14 days after fertilization, so, to try to avoid concerns about research on embryos, scientists who think such research is ethical in limited circumstances have operated under a “14-day rule”–voluntary in the US, mandated by law in the UK–after which embryos would not be destroyed for research.  These “embryo-like structures” may form a primitive streak, it appears.  The situation is similar to “synthetic human entities with embryo-like features,” or “SHEEFs,” which may bypass the primitive streak but raise similar issues of whether something too like a natural human being is being engineered by this work for it to be ethical.

A developmental biologist at Caltech says, the California Institute of Technology in Pasadena. “We will have to confront ourselves with the question of what is a human embryo, and whether these models really have the potential to develop into one.”  The researchers making these synthetic embryos argue that they lack a placenta and other cells needed for development, so could not develop into a person.

At least for now.

Heritable genome editing: a too-short list of 12 questions

Last week, I discussed efforts by a US/UK commission formed to recommend a framework for regulating and monitoring heritable human gene editing.  This commission has called for “expert evidence” to assist them in the task “to develop a framework for considering technical, scientific, medical, regulatory, and ethical requirements for human germline genome editing, should society conclude such applications are acceptable.”  The deadline is September 27, 2019 to make recommendations.  The website to do so appears open to the public. 

Now, I suppose the commission will ultimately decide who qualifies as an “expert,” and several of the questions are decidedly technical.  But I submit that many who read this blog qualify as experts in bioethics or in some aspect of biomedicine, and will be able to offer considered responses to at least some of the questions.  So I encourage readers of this blog to access the link and weigh in.

I have yet to complete my effort.  I started last week, then pulled back in the middle.  Responses to each question appear to be submitted in real time, and the possibility to save work (there are ‘”back” and “next” buttons) for future editing seemed unclear.  And these questions merit careful responses.  So I decided to wait for another day—before the September 27 deadline!

If you would like to mull over possible responses in advance of trying to offer them online, I have copied them here, for advance thinking before submitting at the online portal, or to inform reflection and discussion otherwise:

  1. Which diseases and conditions, if any, do you see as appropriate for human germline genome editing?
  2. If there were to be an appropriate use case for human germline genome editing, what evidence would be needed to proceed to first in human use?
  3. What is the status of editing mechanisms for early stage human embryos (e.g., using different editing techniques, improving homology directed repair, etc.)? What are the factors that predict whether single nucleotide changes or other intended modifications in human embryos will be correct? To what extent will genome editing affect the viability of embryos?
  4. What is the status of the technology for validating that a correct edit (on target characterization) has been made and that unintended edits (e.g., off target effects, mosaicism, etc.) have not occurred in a range of cell and tissue types? If possible, please provide evidence drawn from work on induced pluripotent stem cells, embryonic stem cells, and/or early stage human embryos.
  5. What is the status of generating cell lines from human and non-human germline stem cells?
  6. How might animal models inform the editing in human embryos (inclusive of analysis of phenotypic correction)?
  7. To what extent do different genetic backgrounds affect success and phenotypic outcomes after genome editing?
  8. What is the success rate of full-term pregnancies following pre-implantation genetic diagnosis? What affects this (e.g., age, number of oocytes harvested, technique used, etc.)?
  9. What are the appropriate mechanisms for obtaining informed consent, long-term monitoring of the future children, assessing potential effects in subsequent generations, and addressing untoward effects? Are there best practices from: a) assisted reproductive technologies; b) pre-implantation genetic diagnosis; c) gene transfer research for children; d) mitochondrial replacement therapy; and e) somatic genome editing?
  10. How should we think about the inter-generational medical (e.g., genetic changes to the genome) and ethical implications of human germline genome editing (e.g., potential harms and benefits)? How should the rights of future generations and the wider human population be taken into account?
  11. What international oversight structures would need to be in place to facilitate, in a responsible way, a path forward for germline genome editing?
  12. Are there any topics or issues that are not covered by the above questions that you think the Commission should attend to during its deliberations?

This last question, of course, is the most pregnant of all.  The list of questions is so technical, so question-begging about whether heritable gene editing should be done at all, that the commission should receive carefully-considered reflections on the meaning of the potential enterprise, how the future practice of heritable genome editing should not be a foregone conclusion, and how and why the right answer to “when should we edit human genes heritably” might well be “never.”

By all means, reader of this blog, go online and offer what you reasonably can to this important discussion!

Much going on about heritable genome editing

The first meeting of the International Commission on the Clinical Use of Human Germline Genome Editing was held in Washington, DC on August 13.  This is a US/UK commission convened by the UK Royal Society, the US National Academy of Medicine, and the US National Academy of the Sciences.  Space for in-person attendance at these meetings appears limited, but information is freely accessible on the internet.  For example, the meeting materials and videos from the August 13 can be accessed here, and one can register to be on the Commission’s mailing list at this link. 

It is challenging for anyone with a “day job” whose work is not dedicated to the field of gene editing to try to keep up with developments, so the open access to information is welcome.  The August 13 meeting included numerous basic science discussions as well as some from biotechnology companies seeking to develop gene editing approaches.  As discussed often on this blog and elsewhere, so-called “somatic” gene editing—that is, gene therapy of fully-formed individuals by editing an undesirable gene such as one known to cause disease–appears generally to fall within the existing regime of human research ethics and regulation and pose relatively few unique ethical issues.   The day included industry presentations regarding somatic gene editing, either “in vivo”—involving injecting the gene editor into a person—or “ex vivo”—involving removing cells from a person, editing the cells in the medical lab, then re-injecting the gene-edited cells into the person’s body as a form of treatment.  In neither case is the editing inherited across generations, avoiding the larger issues of manipulating human beings more fundamentally, and, as your present correspondent has consistently argued, unacceptably.

Even for somatic gene editing, however, “getting it right” in the form of editing the genes intended, and only those, and developing approaches to assess and control for longer-term or unintended risks is still a substantial set of tasks, as was described in a presentation by an official from the FDA.

The day also included a presentation from the separate World Health Organization multidisciplinary advisory panel, which held its first meeting in March 2019 with another one having been due this week in Geneva, Switzerland.  At the March meeting, the WHO panel adopted three main recommendations for developing oversight of human genome editing:

  • Establish a structured mechanism for collecting and curating details about proposed and ongoing research;
  • “it would be irresponsible at this time for anyone to proceed with clinical applications [they mean trying to establish a pregnancy or birth] of human germline genome editing”
  • Establish approaches to obtain input from the “broadest possible range of stakeholders” and “explore opportunities for an open, online mechanism for seeking input.”

All that said, the Salk Institute in San Diego is working on a new technique of editing, called SATI (short for intercellular linearized Single homology Arm donor mediated intron-Targeting Integration [say THAT three times fast!], which is expected to be more versatile than the current “preferred” technique called CRISPR-Cas9.  Biologic details between the two differ, but the ethical issues mainly apply to applications, and are therefore the same for both.  But don’t be surprised if you hear about “SATI” for 5-10 minutes in the news sometime.

And scientists at Cornell Medical Center in New York City are trying to gene-edit human sperm to alter the characteristics of children conceived using them.  Pressing ahead with getting ready for the WHO panel’s “clinical applications.”

Mildred Solomon of the Hastings Center has recently added her voice to those pointing out that whether heritable human genome editing should ever be done is not just a matter of weighing benefits vs risks, but involves much more momentous possibilities that should give us pause.  The key graphs:

“Even as [the WHO and US/UK commissions] regroup to produce clearer guidance, however, I sense a shift in the debate. For a very long time, the scientific and bioethical consensus was that we must not do human germ-line modifications—that we should not change gametes and embryos in ways that would be permanent, affecting all future generations. In contrast, somatic modifications, which affect only the person in whom the edits are made, have been mainly uncontroversial.

But that border between germ-line and somatic genome modification is blurring; the zeitgeist feels different. There is a growing sense of inevitability that we will eventually do human germ-line modification and that our only obligation is to wait until it is safe. When that day comes, we may want to make permanent heritable changes to the human species to eradicate otherwise intractable diseases. We should, however, enter this discussion with eyes wide open, considering each application on its own merits and anticipating a wide range of issues that go well beyond safety. Many of these issues are explored in Human Flourishing in an Age of Gene Editing, which will be published by Oxford University Press on August 28, 2019.”

I’m willing to forgive the plug for a book from people at Dr. Solomon’s institution, which is where the editors of the book in question work.  It looks worth checking out.  In the meantime, the US/UK commission has called for “expert evidence” to assist them in the task “to develop a framework for considering technical, scientific, medical, regulatory, and ethical requirements for human germline genome editing, should society conclude such applications are acceptable.”  Follow this link to have a look at their questions.

Baseball Statistics, Racism and 23andMe

I enjoy watching baseball on TV or even listening to a game on the radio. I am amused by the discussions of the announcers, usually around the 8th or 9th inning, particularly when the result of the game is already decided due to a lopsided score. The announcers begin doling out complex baseball statistics. As a former math and engineering student in college, I find this part of the game fascinating.

“Well John, I think this may be the first time Cincinnati Reds player Yasiel Puig has ever been involved in a late-game brawl with the entire Pittsburgh Pirates bench so soon after being traded to the Cleveland Indians earlier during tonight’s game and just 14 days after a Full Moon to boot.”

In baseball, as in life, if you specify an event in sufficient detail with enough variables, you are accurately characterizing that unique event. Some diehard baseball fans argue that with enough baseball statistics, the predictability of the outcome of any future game will become trivial.

In blog-related news, the New England Journal of Medicine recently had two thought-provoking “Perspective” opinion pieces dealing with racism in medicine. The first by medical student D.W. Paul, Jr. is entitled Ghosts of Our Collective Subconscious – What Blackface in a Yearbook Photo Means for Medical Education and the second by Dr. Tara Vijayan entitled ”Browner” – Creating Narratives of Race. Both are unfortunately available by subscription only. Among other things, both articles point out the obvious problems that occur when we reflexively categorize individuals by a single variable – such as one’s skin color – and attempt to predict current or future reality by that single variable. Habitually trivializing people in this manner results in prejudice, bias and bigotry.

This would never happen in baseball. For instance, I have yet to hear the following from an announcer:

“Well John, looking at the stat sheet on this next relief pitcher for the Pirates, it just says he’s white. For our radio listeners, from where I’m sitting, I must say our statisticians have nailed it as he is one of the whitest relief pitchers I’ve ever seen”.

I can promise you that when Yasiel Puig steps up to the plate, he doesn’t care about that relief pitcher’s skin color. He is far more concerned about the speed of his fast ball or the spin rate of his curve ball.

Enter 23andMe (or similar service). For the first time, the average person can send in a sample of saliva and get back a detailed DNA graph and report revealing the multiple countries of origin of their great grandparents and beyond. Having readily available DNA information may not be completely without its problems, and this blog has touched on some of these in past postings. However, one benefit of this technology may well be to convince people that we are a kaleidoscope of genetic material, much more complex, and far more interrelated, than our skin color alone would suggest.

If we are not going to treat our neighbors with the respect and dignity due unique image bearers of God, let us at least stop treating them as if they have only one variable worth considering – the color of their skin – and begin treating them like they have complex baseball statistics. Maybe then we will more accurately describe them, and, in doing so, perhaps better understand and appreciate them.

We should start now and not wait until the 9th inning.

“Safe” gene editing

The New England Journal of Medicine carries a brief article about “Controlling CRISPR-Cas9 Gene Editing” (subscription required).  The upshot: RNA used as a medicine, as in the case of “CRISPR” to edit genes, can hang around well after administration, and alter genes other than the ones intended to be altered.  These “off-target” effects could lead to unwanted clinical side effects.  You’d like to be able to shut the RNA medicine off.  Pharmaceutical companies that make and develop medicines from short RNA sequences have been doing just that—creating “antidotes,” if you’ll pardon the expression (bad use of the word, really—an antidote is to a poison, and the medicines are not poisons)—to reverse unwanted off-target effects of their medicines, should such effects occur.

Using CRISPR for gene editing to treat known genetic disease raises a similar concern, and the NEJM article cites a recent experiment indicating that such a “reversing agent” for CRISPR, if needed, might indeed be feasible.  So, suppose you are trying to treat someone with genetically-caused blindness, and there’s a risk that other genes might be affected.  You could give the “reversing agent” to block that.  Cool.  You’d want to get it into the right tissues—the right parts of the body—but the work described in NEJM suggests that might all be reality eventually. 

One challenge is: these RNA-based agents don’t always get into the parts of the body, or into cells, all that well.  The NEJM writer says that this new work into “controlling” CRISPR-based gene editing “of course, depends on the [reversing agent] delivery problem being solved, but that is a topic for another day.”

It’s been some time since your correspondent worked for a drug company making RNA-based drugs, and I’m not close to the work these days, but I would say that is most definitely a topic for another day.

So, why bring this up in a bioethics forum?  Because it’s one more matter that would need to be considered and addressed before charging into gene editing that can be inherited from generation to generation.  This, as the present writer has repeatedly held, is something that that the human race should never do.

But it’s bowling along.  The latest reports are that attempts to edit genes babies of deaf couples to prevent them from being born with genetic deafness are nigh in Russia.  Understandable, laudable goal, but we should not think that control of the process is nigh.   edium

Embryonic Legerdemain?

Developmental biologist Lewis Wolpert is credited with saying, “It is not birth, marriage, or death, but gastrulation which is truly the most important time in your life.” Gastrulation, simply put, means the embryo develops an axis and distinctly different cell layers. In the human embryo, gastrulation takes place during the third week post-fertilization. Formation of endoderm occurs over days 14-15, and the mesoderm begins to appear on day 16 (see Figure 1-11 here).  Ali Brivanlou, of New York’s Rockefeller University, identifies gastrulation, or the breaking of symmetry in the embryo, as the “major Holy Grail of developmental biology.”

Why is this so? During the third week after conception, the embryo has burrowed into the mother’s womb, and the peering eyes of scientists cannot visualize the events there. With the 14-day rule in place regarding embryo research, laws or guidelines in various locales outlaw or discourage (as in, do not fund) laboratory culturing of embryos beyond that point. So, Brivanlou’s lab “came up with a model of human embryos that is developed outside of the womb and is not the product of sperm and eggs, but the product of human embryonic stem cells that self-organize into complicated structures.”  These embryonic stem cells have formed what appears to be an embryo, but in Brivanlou’s terms, “could never become a baby.”

Dehumanizing the embryo is one of the essential components of making research on embryonic humans more palatable to the public. It will also be en essential step in a workaround of the 14-day rule. It appears that “model embryo” will join other terms such as “embryoids,” “gastruloids,” and “SHEEFs” as some element of humanity that scientists do not recognize as humans worthy of legal protection. Regarding Brivanlou’s “model embryo,” Harvard Medical School’s Dean George Daley calls it a “remarkable tool in a petri dish.” The “tool” with which Brivanlou and others concern themselves is both human and alive; otherwise, would they be interested?

Let’s think about this, using an analogue. If well-trained scientists could produce men and women without chests, what would be allowed? Would they have to call such men and women without chests “human”? Could they use men and women without chests for experiments?  Would the experiments have to be approved by institutional review boards?  Would the rest of us pay the scientists – handsomely – to do this? Could they win prizes?

Technical steps to gene-edited babies

This blog has carried several comments about the prospect of heritable human gene editing.  While nearly no one currently supports bringing such babies to birth—and condemns those who would rush ahead to do so—it appears a distinct minority think that we the human race should, if we could, agree never to do such a thing.  The most cautious perspective is to advocate a moratorium.  Others in favor of proceeding argue that, in essence, with the technologic genie (my term, not necessarily theirs) out of the box, a moratorium, much less a ban, is futile; the “rogues” will press ahead, casting off restraint. 

Advocates of research in this area have argued that a clear, careful, regulated pathway is needed to guide the work through necessary laboratory experiments that should be done first, before making a woman pregnant with a gene-edited embryo, in an attempt to be sure that the process is safe and highly likely to yield the intended result.  Even a moratorium would be, by definition, temporary, leaving the question, “when we will know to remove the moratorium?” to be answered.

A feature article in Nature, accessible without a paid subscription, asks “When will the world be ready” for gene-edited babies.  It walks through scientists’ understanding of what the technical issues are.  It is longer than a blog post, so I can only list key points here.  It is worth a reading by anyone interested, and it is written in sufficiently non-technical language that it’s accessible to the general, non-scientist public.

Key concerns are:

  • How would we be sure that genes that were NOT intended to be edited, in fact were not?
  • How would we be sure that genes that ARE intended to be edited are edited correctly?

These two matters have been addressed to some degree, or could be, in animals, but that would be faster and easier than in human egg cells or human embryos, and the results in animals may be different from what is found in the embryos.  (A further question is how many embryos, observed for how long, would need to be studied to support confidence.)

  • Even if the intended gene edit is made, is it clear that doing so is safe and does not induce other health risks? 

This blog recently reported the UK study that suggested that changes in the gene edited in the twin girls born in China last year might eventually reduce life span.  A criterion promulgated in 2017 by the National Academies of Sciences, Engineering, and Medicine was that the edited gene should be common in the population and carry no known risk (including, presumably, no increased risk) of disease.  Such knowledge is lacking for human populations, and what is believed known about the association of genes with risk of future disease has often been developed in Western populations, and may not apply to, for example, Africans.

  • At least some embryos would include some edited and some non-edited cells.  It would not easily be possible, if possible at all, to tell how many of which were present, or needed to be for the editing to work and not cause risks to the embryo’s development into a baby and beyond.  And what answers were obtained would require manipulating healthy embryos after in vitro fertilization.  The outcomes could not be predicted from first principles.
  • What should a clinical trial look like?  How many edited children would have to be born, and their health (and, most likely, the health of their progeny) observed for how long to get provisional answers before practicing the technique more widely?  Or, would the work proceed as IVF did—with dissemination in the general public, and no regulated research?

A US and UK committee is planned to address these questions, with the intent of proposing guidelines in 2020.  This will be important to follow, but with no chance to affect.  Most of us will just be watching, which leads to the last concern:

  • Is the world ready?

If that means, is there an international, or even a national, consensus, then the answer is clearly “no.”  That almost certainly remains “no” if one asks whether there is a future prospect for consensus.  It’s hard to envision something other than different groups and nations holding different judgments, and, most likely, remaining in some degree of irresolvable conflict.

More gene-edited babies on the way

It is reported this week that a Russian scientist plans to edit the genes of more human embryos intending to bring gene-edited babies to birth.  As with the case in China last year, the intent is to edit a gene called CCR5 that is responsible for a receptor that facilitates initiation of HIV infection.  The stated reason is to prevent transmission of infection from the mother, not the father, as in the Chinese case.  Maternal transmission of HIV is a real risk, but there are other ways to prevent it, with medications.  And, as recently reported on this blog, the risks of editing this gene are not understood, nor are the long-term risks of heritable genome editing.

The science press is saying that someone should put a stop, now, to bringing edited embryos to pregnancy and birth.  But it is unlikely that effective action can be taken.  The public will has not been engaged, necessary medical research controls are not in place, and no one can say just who would have the authority to take what sort of action.

So for the moment there is little else to say.  We will hear of more cases.  We will find out later how we will respond.  Clarity and consistency of that response seem unlikely. https:/

Pragmatism and principle regarding human gene editing

You may have seen in the general press that the gene-edited twin girls born in China last year may have had their life expectancies shortened in the bargain.  The doctor who edited the babies’ genes specifically edited one gene, that is associated with susceptibility to HIV infection.  Their father is HIV positive, but that does not put the babies at any health risk.  Further, the gene editing potentially could have increased their future risk for other infections.  Now, a group in the United Kingdom have analyzed mortality data for about 400,000 people who volunteered to have their genetic information placed in a data bank.  They reported that people who have a gene mutation similar—but apparently not identical—to the change made in the Chinese babies had a 21% lower chance of living to age 76 than people without the mutation.  Now, the average age of the people who volunteered their information for the data bank is said to be 56.5 years, so the implication is that there is a shortening of life expectancy after middle age, for people who have lived at least that long. 

One should interpret the U.K. analysis with caution, but the argument seems to be, “see, we don’t know the risks of human gene editing, so we shouldn’t be doing it.”  And indeed we do not know the risks.  But the argument in fact is, “…we shoudn’t be doing this—at least not yet.”  As Joy Riley pointed out on this blog a few days ago, the goal of a moratorium on human genome editing appears to be to allow the scientists working on the technology to take time to build public trust and consensus for it.  “We shouldn’t be doing this, ever” does not appear to be an option.  Long-term readers of this blog may recall numerous posts over the last few years describing this process of gradual acceptance in the scientific community.  The scientists draw an analogy to the 1975 Asilomar conference on recombinant DNA work, which established guard rails around that work.  But the analogy is flawed.  The risks of the work addressed at Asilomar were more readily defined, with shorter time frames to results, than can be addressed with genome editing.  400,000 middle-aged people’s mortality due to any (unspecified) cause over the ensuing quarter-century?  How many edited people, studied for how long, over how many generations, with what consent process, to determine the risks?  There can be no acceptable definition of the risks prior to actually assuming them.  “The babies are the experiment.”

The correct conceptual framework for human genome editing is not benefit-risk analysis, it is deeper reflection on where we should not let engineering encroach on the human organism.  “Keep your ambition off our bodies,” I suppose.  And when we think in those terms, we should quickly recognize territory where we fear to tread at all, not just slow down.