Styx was formed in 1972, Chicago, and managed to balance elements of soft and progressive rock. The height of their popularity was at the end of the seventies, when they had four consecutive platinum selling albums. Babe is from one of those.
Singer and band founder Dennis DeYoung wrote it as a birthday present for his wife. It was never meant as a song for Styx, but he was convinced by the other members of the band to include it. It was to become their biggest hit.