In column http://www.straightdope.com/columns/031024.html The Illustrious Master finishes off with the comment
If you have a look at the US census on boy’s names http://www.census.gov/genealogy/names/dist.male.first you will see that Mary is a recognised first name for boys. It is distinctly probable that there are or have been male individuals named Mary Smith.
Even worse. The rank of Mary is 699. That means it s the 699th most common firstname in the US census. It beats names such as Truman (716) Joan (759) Jaques (763) Shirley (936) Richie (970) Hank (983) Geraldo (1024) Ambrose (1096) Broderick (1218)
The Master’s one liners will be the death of him I think.