No one is born a Christian, we are all born dead in Adam. Nicodemus, came to Jesus seeking to understand how what Jesus was doing related to what “we” (the Pharisees) know. Jesus told him he cannot see the Kingdom of God unless he is born again. The Pharisees were looking for the Kingdom of Heaven but Jesus told him that first he would need need a spiritual birth, a new heart, the Life of God breathed in to him.