In a way it is also natural. Since the human mind has evolved and developed in order be able to do such things such as perform a c-section. We are able to allow a baby to be born who may, because he or she was saved as an infant be inspired to create the next medical advancement. This advancement could once again somehow prolong human life or improve the quality of it.. So maybe we are not really interfering with it and we in fact are taking part in it.