Well, I think that is *enormously* harder to establish than you are assuming, because so many aspects of the experiment whose role we have no knowledge of, including in the initial conditions, are unmeasured.

I mean the stochasticity is "inherent to development" in the sense that the phenotypic outcomes are only partly specified by genetics and, even under identical conditions, you would still get variation in outcomes

Yes and I'm disagreeing with that :) I don't think developmental biologists have discovered a new source of stochasticity in the universe. Biological systems are complex and have many factors we don't know about and are unable to measure. But fundamentally they are no different from other systems.

Just because we can't currently measure the factors that affect eg molecular concentrations, cell morphologies, differential growth, doesn't make them fundamentally different, or imply that their variation is somehow partitioned off from the world that we can measure.

Are you proposing that this 3rd category of 'developmental' variance is somehow independent of either genetic or environmental factors? What's the source of it then, quantum mechanics?

So, in my view, handedness is a great example of a trait where the relationship between genotype and phenotype is just inherently probabilistic. What you inherit is a likelihood, but how that plays out depends significantly on chance. (No hidden variables).

I wrote about the genomics side of the NHS health plan here (www.linkedin.com/feed/update/...) - it is more than the newborn sequencing side - and probably most importantly it is well thought through

5/ How should the scientific community respond?
Seek immediate IRB guidance.
Demand that universities & professional bodies speak out.
Use legal challenges where possible.
Avoid self-censorship & anticipatory compliance.
Speak with one voice—ethical standards must be maintained.