If you mean trading the natural cycles of reproduction for our hatching rebirths, it was so long ago now that there are no records left detailing the exact means of the transition. That's part of the problem: how does one undo such a change when we no longer know how it was initiated? Beyond that, the preceptors would sooner kill any who try to restore the cycle than lose their power. They are our governing body, you see--the ones who raise and teach the hatchlings.

[ She's very certain that they had a hand in the downfall of the last elder who tried to change the status quo. ]

They might be content to let our species fade into obscurity, but not all of us are.