"All" does not INTRODUCE a sufficient condition in this case, but it does REFER TO as sufficient condition. Let's pay attention to the wording of the sentence.
"Normal full-term babies are all born with certain instinctive reflexes..."
Another way to say that would be "All full-term babies are both with certain instinctive reflexes..."
The ALL is referring to "normal full-term babies" and not to "certain instinctive reflexes"
"Normal full-term babies" is the sufficient condition
