This prevents incest and inbreeding. The destroyed remains of their ships orbit Galifrey 2 and act as a warning to any and all invaders, they understand that Galifrey 2 is protected and that trying to invade it is a death sentence. It was his Human companion Clara that helped him kill the parasite god Akhnaten, it was also Clara that gave him his extra set of regenerations. When the Humans of Galifrey 2 die of old age their bodies are burned ( no burials ). He has a personal forcefield that’s just as strong as the forcefield that protects his ship. He also surrounded the planet with weather manipulation devices that fly underneath the satellites. Earth history will claim that these missing Humans died during these destructive events, no one will ever know that they were saved by an alien.
