There are lots of ways for advanced beings to avoid conception.
They did not believe that really advanced beings would possess organic bodies at all.
We've learned there were very advanced beings living back then.
These inconsistencies give us reason to suspect contamination by other advanced beings than ourselves.
Now we've found advanced beings who don't belong here any more than we do.
But keep in mind, if there are other advanced beings out there, then we're a target.
If the higher density is right, that means advanced beings would inhabit about one in every 400,000 stars.
A race of beings far more intelligent and advanced than us built that spaceship.
An advanced human being, with the right to control my own life.
Our fate was decided by the advanced beings with whom we shared our world.