Babies should ideally come out head first so that their head shrinks and squeezes to allow their tiny body and head to squeeze through the mother and come out healthy and safe.
When a baby comes out feet first the head may get stuck in the birth canal and cause the baby to suffocate or die or at least have health issues.
If the baby is not in the position to come out head first then a C Section will usually need to be done to safely remove the baby from the mothers womb.
Most babies naturally get into the correct position to be born head first so there's usually no problem with the births but in some rare cases the baby may be in the wrong position and want to come out feet first and in those cases the doctor will either need to force the baby out or do surgery to remove the baby.