"The chances are equal" to get all demon babies, no matter the type of newer or older babies. This means you don't have more of a chance to get one baby of another. Here are the types of babies you can get:
Evilina, Impward, Meandi, Whinona, Badbara, Cryana or Tearesa
Images taken from https://tibia.fandom.com/wiki/Demon%27s_Lullaby in which you can learn more about the world quest.
This question was asked in the Tibia forums and answered by CM Mirade as seen in my source- https://www.tibia.com/forum/?action=thread&postid=38674408#post38674408
Congrats shawtay on 10,000 reputation points!!!September 15, 2020
Outstanding Contribution contestSeptember 14, 2020
Hints for posts that received a down-voteAugust 15, 2020
I've received a down-vote - how can I fix it?August 14, 2020