The umbilical cord is normally cut very soon after delivery. You are getting hung up on a detail of the birth process. But anyway, the change is that the baby has normal human functions that were not present in the womb: it is breathing on its own, it is feeding orally, it has normal excreation, it has vocal expression, etc. It has air on its skin, it has been seen by the unaided eye, it is beginning the process of becomming aware of the human environment in which we all live...etc.
You are arguing about details which will always be open to conflicting interpretation, and you are missing the main point here, please see post #639.
My son did none of these things, at least initially, yet you said it was not permissible to abort him. He did not cry, did not breathe, had no self awareness (at least nothing different than he had a moment earlier, still in utero). You're faced with a logical flaw in this case. Either you can abort him or not, and it is up to you to say why or why not.
The problem is that you have dehumanized an individual based on circumstances and attributes whose merit or non-merit is the decision of an external agency. IOW, you have removed the humanity from an individual which is clearly human in its own right. Your system of ethics seems to vest the humanity of individuals in an external agency, not within the individual him/herself.
Huamnity has been down this road before, and the result has been only rivers of blood. For if you insist subjecting the "human-ness" of individuals to narrow definitions of one sort or another, the result can only be measureless destruction. Because the scope of those narrow definitions can change at a whim, often based on who at the time has the power to do so. Only by defining humanity in the most general, complete terms, encompassing the entire sweep of human existence, from the first flicker of life to its final and irreversible extinguishing, can such a holocaust be avoided.