One of the main new features of Petz: My Puppy Family is that you can cross-breed your pets. To do this, first of all you need a male dog and a female dog. They need to be your pets. Then, you need to try and make them friends with each other.
Making Friends[edit]
Your dogs automatically interact with each other, but they may not necessarily be good interactions. If your dogs like each other, they will play together and lick each other. All ages of pets can be good friends with one another, but only adults are able to breed.
When the face between the two pets (on the top screen) has become a open mouthed smile, your pets should be able to breed. They will go up to each other and love hearts will float around. Then both the screens on the DS will show a large pink love heart, and you will get a message telling you that a puppy has been born. You will then see the adoption certificates for both the parents, and you need to tap Signature to put a paw print on each one. Then you will see the puppy with it's mum and dad. If the parents were different breeds, it will be cross-bred.
After the puppy is born, the face between the two parents will return to a straight face, and you will need to build their relationship again if you wish for them to have another puppy.