One of the main problems is that people get transformed into a bunny after they get a few eggs, so you cannot tell if their character is male or female. Which, as I’m sure you can imagine makes it tiresome to ask each and every one if they can take off their bunny transformation so you can apply the ears if they’re female.
So, I made a little addon (my first) that does a small edit to the tooltip you see when you mouse-over players. It will replace the “Level xx race class (Player)” line with “Level xx gender race class (Player)”.
I’ve uploaded this to WoWInterface. If you check it out, let me know what you think!