Headscratchers / Yoshi's New Island

• Why didn't the two adults in the intro keep Baby Mario and Baby Luigi instead of just leaving them there?
  • They probably knew another couple was expecting the babies and keeping them would make the original parents very sad. How would you feel if you were going to have children and other parents kept them due to a mistake? There's also the possibility that they were going to have babies themselves and were scared that the stork would deliver them to other parents since they were already taking care of Mario and Luigi.
    • The couple says they weren't expecting any babies. However, with that in mind, they might not have had the means to take care of babies.