In our view, genome editing in human embryos using current technologies could have unpredictable effects on future generations. This makes it dangerous and ethically unacceptable. Such research could be exploited for non-therapeutic modifications. We are concerned that a public outcry about such an ethical breach could hinder a promising area of therapeutic development, namely making genetic changes that cannot be inherited.I think there's general agreement that the current procedures aren't safe enough to make it worthwhile. I can agree with the safety issue.
However, I'm not so sure about the "ethical" issue because that's complicated. We all agree that is it unacceptable to do something that endangers a patient and future offspring. We can agree that it would be "unethical" to modify a patient's germ line if we don't have a good idea of the possible ramifications. But that's really just another way of saying that we shouldn't do something stupid.
Ethical issues are hard to pin down but they usually concern conflicts between different views of what is right and what is wrong. If the vast majority of people agree on what is right then the presence of a few renegades does not make an ethical issue. What about "non-therapeutic modifications" of the human germ line? If some people think this is permissible and others think that it is not, does that make it an "ethical" issue? Of course not, not all disagreements are ethical issues.
Patient safety is paramount among the arguments against modifying the human germ line (egg and sperm cells). If a mosaic embryo is created, the embryo’s germ line may or may not carry the genetic alteration. But the use of CRISPR/Cas9 in human embryos certainly makes onward human germline modification a possibility. Philosophically or ethically justifiable applications for this technology — should any ever exist — are moot until it becomes possible to demonstrate safe outcomes and obtain reproducible data over multiple generations.I don't think any reasonable person disagrees with this statement. This is a safety issue.
I'm interested in the part that says, "Philosophically or ethically justifiable applications for this technology—should any ever exist ...." The implication here is that there are serious ethical questions about whether one should engage in germ line editing/modification. The authors give the impression that there might be strong ethical objections even if the procedure were safe.
They go on to say ...
Because of such concerns—as well as for serious ethical reasons—some countries discouraged or prohibited this type of research a decade before the technical feasibility of germline modification was confirmed in rats in 2009 (ref. 9). (Today, around 40 countries discourage or ban it.)What are those "serious ethical reasons"? Imagine that modifying the human germ line was proven to be perfectly safe and we knew exactly what the consequences would be for future generations. Having disposed of the safety issue, what "ethical" reasons are there for banning the procedure?
Keep in mind that this is a form of thought experiment so don't quibble about safety. If you think there's still an "ethical" problem then try and explain what you mean by an "ethical" problem. I don't see any reason to ban this procedure if it's safe. There's no "ethical problem that I can see. You may not think it's a good idea to modify the germ line but is that a reason to prevent others from doing it? Is it an "ethical problem" for you?
Why is this important? It's important because there's increasing pressure to incorporate "ethics" into science classes and often the "ethical" questions aren't really ethical question at all.
Teaching Ethics in Science: Science v Technology
Teaching Ethics in Science: Science v Technology (Part 2)