This
song has a bit of an interesting
recording
history, especially when it comes to the last
two lines in the last non-
ob-la-di stanza.
The Beatles were trying to record this song, and they had nothing but troubles. One member would mess up somewhere, or they'd have acute technical difficulties, and so forth. Finally, after a couple dozen attempts, at something like 3 AM, they finally got what seemed to be a perfect take.
When they were shutting down the studio for the night, Paul made the comment, "Oh shit." He suddenly realized that in the last verse he had accidentally reversed the roles of Desmond and Molly.
So John had the brilliant insight along the lines of: "Let's just leave it as it is. People can just think that Desmond's a transsexual or something. It'll be fun."
And so they left it as it is, and called it a night.