I had thought that the saying ‘Accidents will happen in the best regulated families’ was a vulgar reference to children born unexpectedly. The Oxford English Dictionary records accident being used in just that way in the middle of the 19th century. On its own, ‘accidents will happen’ dates from at least as far back as 1705, and the Lady’s Magazine for 1791 gave this humorous version: ‘Mistakes will happen in the best regulated families; I have taken my opera fan to church.’