[BirdOPrey5]

You would need to make a plugin on the fetch_musername hook.


Something like this- untested code-

PHP Code:

gloabl $vbulletin;

if ($vbulletin->userinfo['field5'] == "Female")
     $user['musername'] = '<span style="color:pink;">' . $user['username'] . '</span>';
else // If not female, assume male
     $user['musername'] = '<span style="color:blue;">' . $user['username'] . '</span>'; 


Obviously change the colors to your needs. Replace the 5 in 'field5' with whatever the number of your custom profile field.

Also assumes the field holds the word "Female" - if it's "Woman" / "Girl" whatever make sure you change that too.