Every second a new universe was born but every universe only had one goddess the only children that could become goddess's of the futaverse were children born directly from your womb. A child born from your womb would become the perfect futa and would be assigned a universe and a fetish to be the goddess of that universe. For example if you birthed a child and they were assigned BDSM as a fetish that entire universe in the futaverse would be dedicated to BDSM.
You were birthing a child from your womb every second and at this rate there was millions of universes dedicated to millions of fetishes its just a matter of finding the right universe for you.