In Zodiac Pet Masters, there are 12 different Zodiac pets, each available in male and female versions. From level 3 (LV3) onwards, you can pair pets to produce offspring automatically:
Pair two LV3 pets to get one LV1 offspring of the same Zodiac type each week.
Pair two LV4 pets to get two LV1 offspring each week.
Pair two LV5 pets to get three LV1 offspring each week.