Actually, after birth, the baby is still attached to the mother via the umbilical cord. Are you proposing that the baby is still part of the mother while she’s outside of the womb and breathing air because she’s still attached? That’s probably not what you mean. Then what makes the baby outside of the birth canal…

So until the baby is born, the mother has two heads, two hearts, four arms and four legs? Despite the fact that the baby has a completely different DNA, likely a different blood type, a 50-50 shot of having a different gender? And if the baby is male, does the mother all of a sudden have a penis?