Instructions
Turn on your Nintendo DS with the My First Baby Steps game inserted. Select the map of the house in options.
Select the DS chip icon in the bottom right corner. The bottom of the screen should display instructions to press the R button while simultaneously holding down the X button and B button. Follow those instructions.
Select the highlighted button at the bottom of the screen. You will be given the option to delete the baby with a statement that says, "Delete Profile." Confirm this and your profile is deleted. You can now start the game from the beginning with a new baby.