I enabled the requires question and answer in web.config file on the registration page ( requiresQuestionAndAnswer="true" ).

I decided to create a Parent Portal, filling all necessaory informations ( there is no entry fields for Question and Answer ), it write out the following error:

The answer specified is invalid. Please specify a valid answer to the question.

I just changed the indicated UserName to one username that already defined (say Saeed1) but has been deleted after a while, and the new parent portal has been created.

I deleted the new created portal, then deleted it's admin user name (Saeed1). If I register a new user from the registeration page with the same user name (Saeed1) but with different other data(name, family, email), all old-info of this user name have been retrieved and assigned to this new user.

I think it's better to first disable question and answer, then create the new portal, and then re-enable Q-A.