Erik Moeller, 29/12/2011 03:35:
[*] For even more technical detail: The gender setting in the user preferences, and taking gender into account in the localization, pre-dates the gender localization of the User: namespace. The User: namespace localization by gender was just a particularly tricky case of taking that setting into account and was only deployed with MediaWiki 1.18.
Thanks to Nikerabbit I've added a list of languages which currently use this feature, for the sake of clarity (it wasn't documented anywhere): current location https://www.mediawiki.org/wiki/Manual:MediaWiki_architecture#Interface_langu... (end of the paragraph).
Nemo