In cryptocurrencies, the process of generating new coins or tokens is called minting.

Kitty Minting

CryptoKitties mints new generation 0 kitties and also exclusive kitties for special promotions or gifts. Minted kitties have no parents, they are created by calling special functions in CryproKitties core contract. There are hard limits in the contract: 45,000 normal generation 0 kitties (clock kitties) and 5,000 promotional kitties can be minted.

Minting is the only way to introduce genes 00-15 and 31 into the game.