And my version has a different bridge verse after the Grandad one, and then a couple of different ones to finish:
And on your honeymoon you couldn't start too soon Kids they said was heaven's gift to man But you'd have done a bunk and his nibs would be a monk If you knew that you'd be bringing up the hordes of Genghis Khan!
You tell 'em how a baby's made ... they'll tell you how it's not! They've read your naughty magazines and understand the plot And with Action Man and Cindy they can demonstrate the lot Just remember, they're only kids.
And now the years have passed and all your little birds have flown You're off the tranquilizers and it's home sweet home And then they come and visit you ... with children of their own! Just remember, they're only kids!
I guess, like the folk process, the song varied over the years. Always gets a laugh though. Vale Fred!