Load your character up on this. It'll tell you specifically what breed your pet, in particular, is.
3-12 male, 13-22 female, as the above poster said.
This is awesome! I was using warcraftpets to find the breed ID but I still didn't know if it was male or female. This says the exact number! Now I dont have to worry about nameing a male pet with a female name... >w>
There might be an addon that'll do the same thing in game, but I don't know which one.
The BreedID addon I use only gives it to me in an an alphabet format (PP, P/B, P/S, blah blah blah.)
... Also I kinda don't care. Pasquirrelio is a boy even if BreedID says he's a girl.
If it's eventually visible in default UI then he's trans and Blizz can bite me