Well, the exact date of Jesus' birth is not recorded in the Bible. However, the traditional date of December 25th was chosen because it was believed to be nine months after the Annunciation, which is the Christian celebration of the announcement of the birth of Jesus by the angel Gabriel to Mary. So, in a sense, December 25th is both the birthday and the conception day of Jesus. But it's important to remember that this date is a matter of tradition and belief, and not necessarily a historical fact.