Do Gaia worlds spawn less often in low density galaxies?

This may be just a coincidence, but I started a 1000 star game with only 12 other empires (all advanced AI start) and there are no Gaia worlds in my whole third of the galaxy. This is quite unusual compared to my other playthroughs which had higher density of AIs. Is it possible Gaia worlds correlate with empire density to allow greater colonization flexibility?