But at that point your argument is almost tautological - all children born alive are fit to survive ? Being born with such huge asymmetry (missing limbs) and still surviving is low probably (impossible without a head).
I'd say a more convincing argument for deterministic machinery is identical twins - I don't know how much variation there is to put in numbers.
"But at that point your argument is almost tautological"
Yes, that is the point: biodevelopment is deterministic and computational. Watch the Michael Levin video linked above: they cut the head of a planarian worm, it grows back a head; they cut the tail, it grows back a tail; they cut the tail and the head and change the bioelectric gradients, it grows back two heads or two tails.
I'd say a more convincing argument for deterministic machinery is identical twins - I don't know how much variation there is to put in numbers.