How can we hide administrator users from being seen in the list of users?
Showing admin accounts gives hackers a better opportunity to try hacking admin accounts.
In fact, it might be a good idea to have a file on the server that contains allowed IPs for the highest level users such as admins.

Also, listing users by gender is a little odd. Is there a way to add 'List all' and make listing by gender more of an option than the only choice?

Finally, could there also be an option to not allow users to list all members and only their own friends? That would come in handy if a site gets popular. Showing the entire list of members is unneeded.