a simple snippet to start with...

Hi, 

could someone give me some clues on how to do this simple page or plugin ?

The page should only display that info: 

Hello {username},
Your gender is {gender}
your avatar is {avatar}
your role is {role}

regards

Although it could be done with a bit of coding, the question is why do you need it? All that information is available on a members profile as soon as they have access to their account.

At best, a member would only look at the page once and creating pages that receive very little attention should always be avoided.