Well it's normally 24hrs OF HIM BEING AWAKE after the baby was born. That does not include when he is asleep or paused. Your adult will leave at midnight.
I don't know why everything is midnight! Why can't it be 11pm or 6am or something like that? They have to make it like a fairy tale don't they!?
The parents leave at midnight after they've been with the baby for at least 24 hours-after you had your tamagotchi unpaused for at least 24 hours, set the time to 11:59 P.M. and wait a minute. The light should turn on and the parent should be next to the sleeping baby. Wait a few more minutes - be patient! Soon, the parent will float up out of the screen to "Tamagotchi Planet" You took care of your character well!
Then, when you turn the time to 9:00 A.M. or in the morning - if the baby does not wake up turn the time to later that morning. You'll be able to name the baby and the tamagotchi will tell you if the character baby is a Girl or a Boy. I hope it is clear now!
The time the tama's parents leaves is in about about 2 days.Like evrybody else said,you can make the parent stay longer,but that would only be delaying your new baby's growth.
*sigh* Everyone keeps repeating stuff that's already been said, just to be "The Best"- please stop all the nonsense- there is no "best person" on tamatalk! You're all awsome!