We've created an entirely separate guide to explain Breeds and Gender
. Click the link to check it out!
TLDR; Genders are pre-assigned to certain groupings of pets (breeds). Breeds 3-12 are male, while 13 to 22 are female.
It's not something we can control at the moment. Developers implemented them "just in case" they want to add even more depth to the whole "breed" concept in the future (ie: breeding pets).