In addition, the gospels of Mark and John do not contain a birth story at all. On the other hand, advocates of Biblical criticism would emphasize differences and conflicts among various passages in an effort to understand why they disagree. But it was rejected as invalid. Thus it was not included in the gospel. Apparent conflicts between Bible passages motivate conservative Christians to try to harmonize the verses.
Discrepancies are useful to liberal theologians.
They believe that they can use Biblical criticism in order to improve their understanding of the origin of religious beliefs and the development of religious traditions. A Revolutionary Biography. R.W. Funk, Roy Hoover and the Jesus Seminar.