Both songs were up for the inclusion of "The White Album," but, for some reason, Paul's "Mother Nature's Son" won out. John's "Child of Nature" lyrics were too close to Paul's song.
Child of Nature later reappeared on John Lennon's solo album, "Imagine," with new lyrics, called "Jealous Guy."
Personally, I liked John's song better (heard it on "The White Album Acoustic Demos"), it had a better rhythm. How did Paul win that battle? Did John simply relent and say, "okay, Paul," or did George Martin veto John's song in favor of Paul's?