Baby is one of the two roles players can pick when joining the game, the other one being Parent. Players can also change to the Baby role by either entering an Age-O-Matic in the Nursery, buying and using one in their home, or by clicking the "change to a Baby" button located in the bottom right of the dress up menu.
As Babies, players have several needs that periodically appear, just like those of Pets, however babies are more limited in completing certain tasks such as eating or drinking, as they have to manually eat or drink several times to satisfy their needs, and can't eat off of pet bowls. While playing as a Baby, players cannot pick up their pets or their family members' pets or babies, even when a stroller is equipped. Parents can pick Babies up or use a stroller to pick them up. Unlike pets, any player can pick up a Baby if the Baby isn’t in a family, if the Baby is in a family only Parent family members can pick them up. As a Baby, they can ride players that have the Parent role, and are either in the same family as the Baby, or if both the Parent and Baby aren’t in a family.
Parents can adopt babies and take care of them by joining the Baby’s family. Before the pets update, taking care of babies was the only way players could earn Bucks.
- When a Baby rides a pet, it stays the same small size, unlike a Parent where it grows larger.
- When a Baby rides a vehicle, the vehicle shrinks to the Baby's size, with the exceptions of the Traveling House, the Ice Cream Van, and the Choo Choo Train. Parents and Pets can still ride a Baby's vehicle, even if the Parent can't fit inside the vehicle.
- A Baby is slightly less than half the height of an Parent.
- A Baby can have all the tasks a Pet can, and vice-versa.
- Babies used to spawn in the Nursery, and they do in Legacy Adopt Me.
- There is an Age-O-Matic Machine in the nursery, meaning players do not have to spend money to put one in their house when they could use the one in the nursery.