<P> "John Doe", "John Roe" or "Richard Roe" (for men), "Jane Doe" or "Jane Roe" (for women), and "Baby Doe", "Janie Doe" or "Johnny Doe" (for children), or just "Doe" or "Roe" are multiple - use names that have two distinct usages . Firstly, and especially in the United States, Canada and Ireland, they may refer to an unidentified person, or a party in a legal action whose identity is being withheld officially . In the context of law enforcement in the United States, such names are often used to refer to a corpse whose identity is unknown or unconfirmed . Secondly, such names are also often used to refer to a hypothetical "everyman" in other contexts, in a manner similar to "John Q. Public" or "Joe Public". </P> <P> In other English - speaking countries, unique placeholder names, numbers and / or codenames have become more often used in the context of police investigations . This has included the United Kingdom, where usage of "John Doe" originated during the Middle Ages . However, the legal term John Doe injunction (or John Doe Order), has survived in English law and other legal systems influenced by it . Other names used informally such as "Joe Bloggs" or "John Smith" have sometimes been informally used as placeholders for an everyman in the UK, Australia and New Zealand, such names are seldom used in legal or police circles in the same sense as John Doe . </P>

Why do they use john doe and jane doe