Board Thread:General Discussion/@comment-25028999-20140801192152/@comment-24986099-20141008012843

Since gems don't reproduce, it's entirely possible that Steven is the first gem to ever be born and Rose didn't even know that she had to give up her physical body in order to bring Steven into the world.

As for why they might need to give up their physical bodies...

Since gems don't have the abilty reproduce, it's possible Rose created Steven with the power of her gem and allowed him to become the default product of creation when regeneration occurs.

So Rose (And Greg) created Steven and Rose allowed him to become the default appearance and consciousness the gem loads upon regeneration, she just needed to force herself to retreat into her gem and upon regeneration Steven took her place.

I do believe that Rose is still alive within Steven's gem but since her physical body cannot occupy the same space as Steven's body; she can't regenerate until his gem is removed from his body.