I've seen many sites claiming that Natalie Merchant's song "Wonder" is supposed to be about a child with Down Syndrome. I haven't seen anything concrete to say either way, but the lyrics can certainly be applied to a child with DS.

Wonder by Natalie Merchant
Doctors have come
from distant cities
just to see me
Stand over my bed
disbelieving what they're seeing
They say I must be one if the wonders
of God's own creation
And as far as they see they can offer
no explaination

Newspapers ask
intimate questions
want confessions
They reach into my head to
steal the glory
of my story

They say I must be one if the wonders
of God's own creation
And as far as they see they can offer
no explaination

I believe
Fate smiled and Destiny
laughed as she came to my cradle
"Know this child will be able"
Laughed as my body she lifted
"Know this child will be gifted
with love, with patience, and with faith
She'll make her way"

People see me
I'm a challange
to your balance
I'm over your heads how
I confound you
and astound you
To know I must be one if the wonders
of God's own creation
And as far as you see you can offer
no explaination

I believe
Fate smiled and Destiny
Laughed as she came to my cradle
"Know this child will be able"
Laughed as she came to my mother
"Know this child will not suffer"
Laughed as my body she lifted
"Know this child will be gifted
with love, with patience, and with faith
She'll make her way"