John Doe is sometimes used to refer to a typical male in other contexts as well, in a similar manner as John Q. Public, Joe Public or John Smith. The female equivalent of John is Jane Doe, whilst a child or baby whose identity is unknown may be referred to as Baby Doe.
The Doe names are often, though not always, used for anonymous or unknown defendants. Another set of names often used for anonymous parties, particularly plaintiffs, are Richard Roe for males and Jane Roe for females (as in the landmark U.S. Supreme Court abortion decision Roe v. Wade).
The name "John Doe", often spelled "Doo," along with "Richard Roe" or "Roo" were regularly invoked in English legal instruments to satisfy technical requirements governing standing and jurisdiction, beginning perhaps as early as the reign of England's King Edward III (1312–1377). This particular use became obsolete in the UK in 1852:
Bearing the actual name John Doe can cause difficulty, such as being stopped by airport security or suspected of being an incognito celebrity.