Instructions
Establish a bond with your cats. Feed them, brush them and play with them.
Play with all three cats at once. Let the animals interact and play together on the same screen. If you have two cats that are the opposite gender, have them interact more often.
Take your cat to the park. Let the cat get to know other cats in the game. Target the male cats by interacting with them every time you visit the park. You are creating a bond with the other cats.
Wait to see if your female cat has kittens. If she does not, try again with a different cat as the game does take chemistry into consideration when breeding.