It seems it is all the fault of that well-known sexist William Shakespeare. Academics at the University of Surrey, who appear to have plenty of time on their hands, have been investigating why male precedes female so often in name pairings – as in Mr and Mrs, or Jack and Jill, or Romeo and Juliet. And it is the last of these that holds the clue.
Apparently it was the “sexist grammar” of the 16th century that put us into the habit of giving precedence to the man (who still leads the way in 79 per cent of pairings, say the academics, courtesy of Google) and we have never quite got out of it. It is this “outdated sexism” that prompts us to write “Dear Sir or Madam”, rather than the other way round. Then again, it may just be that it trips easier from the tongue or pen like that. Who knows? Indeed, who cares?