Just thinking about some of the miracles that are associated with the birth of Jesus.
The announcement, birth and naming of John the Baptist
The timing of the birth of Jesus (in God's predetermined time, e.g. Gal. 4:4)
The angelic appearance and announcement to Joseph
The angelic appearance to Mary
The miracle of conception without humans means
The announcement to the shepherds
The visit of the wise men and the star marking the place when the child had been moved
These are just a few things that come to mind, and some of them encompass more than just the things listed above (for example, the visit of the wise men includes God's warning to them).
What miraculous events do you associate with the birth of Jesus the Christ of God?