Zooby Newborns start at stage 0 and can grow up to stage 48 with Brain Booster Stars. Zooby Babies start at stage 24 and can also grow up to stage 48 with Brain Booster Stars. There is no need to purchase a newborn and a baby separately, unless you are looking to extend your family.
Each Brain Booster Star is good for one baby & one stage only. Once a Star has been assigned to a baby the star is used & cannot be reassigned to another baby. The Brain Booster Star cannot be used again by the same baby.
You may only assign one Brain Booster Star to your baby at a time. If you assign an additional Brain Booster Star before the first Star has been fully used, you would have wasted the first assigned Star.
At any point you can see what stage your baby is currently on. If your baby is in the middle of using a Brain Booster Star you can see how much time is left before a new stage is learned by clicking your baby and clicking Hover Text, Show Stage. If the hover text says "Not currently growing" that means your baby does not have a Brain Booster Star activated & will not grow until you purchase & assign a new Brain Booster Star.
Your baby will randomly play the stages she learned on her own; however, you may also use your baby's menu to play your baby's stages.
When your baby learns new stages she will forget old ones. For example, once your baby can crawl she will no longer roll over. Once she learns to say Mama, she will no longer babble like a newborn. By stage 24 and on she will no longer forget old stages.
Parents or anyone on your baby's friends list may also purchase and assign a Star to your baby.