How to create user categories in Q&A Plugin?

I'm looking to create user types in Q&A - so that questions can then be sorted according to category.

In this case, I want each user to have a gender variable assigned upon signup that is immutable.

Then, users will be able to sort questions by gender, and answers will also be grouped by gender upon display.

I understand some of this functionality can be achieved through Wordpress' native assignment of roles such as subscriber / editor, etc.

Which route would be easier: adding a variable to Q&A, or using a separate plugin to add extra WP user types and then integrating with Q&A under 'Assign Capabilities'? If I choose the second route, what sort of code would I need to add to the Q&A plugin to display answers grouped according to WP user type?

Thanks in advance for any advice.

The site is in Polish and (more or less) works at http://www.evolove.pl