The Grays are one of the oldest of the clades, tracing their history back to the beginning of readily available biosculpting technology. At the time, a relatively small number of individuals chose to alter their form to duplicate the alleged appearance of the so-call 'grays', hypothetical alien beings of humanoid, but inhuman appearance.
As humanity spread outward to the stars, and subsequently failed to encounter any beings matching the description of the grays, the Gray bio-form waxed and waned in popularity, virtually disappearing for centuries at a time only to reappear again as historians rediscovered it and spread the design across the Known Net. Over time the idea of the Gray has changed from one honoring the alien visitors waiting among the stars, to a sort of bio-formatic joke, to an acknowledgment of the vagaries of the human imagination.
For the last several thousand years, the Grays have existed as an acknowledged clade, with a sustained population of some 600 billion. They are mostly concentrated in the Low Middle Regions of the Sophic League with a number of smaller enclaves in the Biopolity and Orion Federation.