A soloist in our choir is doing a Michael Card song called Joseph's Song tonight. It's a little too maudlin for me, but a lot of people like it.

JOSEPH'S SONG
(Michael Card)

How could it be this baby in my arms
Sleeping now, so peacefully
The Son of God, the angel said
How could it be?

Lord, I know He's not my own
Not of my flesh, not of my bone
Still Father let this baby be
The son of my love.

Father, show me where I fit into this plan of yours
How can a man be father to the Son of God?
Lord, for all my life I've been a simple carpenter
How can I raise a king?
How can I raise a king?

He looks so small
His face and hands so fair
And when He cries, the sun just seems to disappear
But when He laughs, it shines again
How could it be?

Father, show me where I fit into this plan of yours
How can a man be father to the Son of God?
Lord, for all my life I've been a simple carpenter
How can I raise a king?
How can I raise a king?

How could it be this baby in my arms
Sleeping now, so peacefully
The Son of God, the angel said
How could it be?
How could it be?


It Wasn't His Child and Joseph's Lullaby are other similar songs.

Source: http://www.christmas-songs.org/songs/josephs_song.html