According to wikipedia: However, when his [James] parents married, it was announced that, in accordance with their wishes, their children would not be styled as Princes or Princesses with the style...
The title of prince or princess is granted by the reigning monarch, and indeed, Prince Edward's heir, James, has been granted the title Prince James of Wessex.
The term "prince" is used in the UK to refer to certain members of the royal family. William became a prince essentially by being born. Kate is a princess because she's married to a prince, but it's...