This is how the birth of Jesus Christ came about:
His mother Mary was pledged to be married to Joseph,
but before they came together, she was found to be
with child through the Holy Spirit.

Because Joseph, her husband was a righteous man and did
not want to expose her to public disgrace, he had in mind
to divorce her quietly.

But after he had considered this, and angel of the Lord
appeared to him in a dream and said,
"Joseph son of David, do not be afraid to take Mary home
as your wife, because what is conceived in her is from the
Holy Spirit." She will give birth to a son, and you are to
give him the name Jesus, because he will save his people
from their sins.

All this took place to fulfill what the lord had said through
the prophet: The virgin will be with child and will give birth
to a son, and they will call him Immanuel"--which means
"God with us." (Matthew 1:18-23)

Found at: AllSpirit