GEne Roddenberry participated in the private closed group channelings of "ET sources" done by Phyllis V. Schlemmer. Much of the original Star Trek lore comes from these sources, way before the first Star Trek script was written.

This is briefly discussed in the book "The Only Planet of Choice: Essential Briefings from Deep Space " by Schlemmer.

As there were other people present, they have corroborated these claims : dates, materials, presence of Roddenberry.

If you dig, you shall find.