wait sorry i'm really dumb and this concept has confused me, how is it that only john and karkat have to do ectobiology? how did the baby meteors exist in the other universes without john/karkat's creating them? is it just skaia's portals, carrying the babies to a different game session from the original one?

When a scratch is initiated Skaia changes the portals that the babies go through so the babies only need to be created once.