My First suggestion would be Johnny Mathis, When a child is born! (I'd like to hear New Model Army do a cover of this actually.)
Other suggestions would be "Zombie" by The Cranberries, "Imagine" by John Lennon or, for sure, "All Babies" By Sinead O, Connor.
It would be an interesting call to create a compilation C.D. for The Birth, informed by the most called for songs with lyrics that resonate for everyone who becomes a part of this, by visiting the online exhibition and reading The Book of The Birth as it emerges. (The first chapter will emerge on the Vernal Equinox: 20/03/08)
So if you're in a band...