Yes, a new born baby has to cry otherwise her brain will not get oxygen immediately and this will bring serious complications later. You see when the baby is in the womb it doesnt breath through the nose but by umbilical cord so when it comes out there is no oxygen going in through the nose since the baby doesnt know how to breath so the nurse will hit their tiny buttocks and they will respond to the pain will a yell which automatically opens the nose and the lungs start pumping oxygen.