I quote from pages 135-136 of the Sept. 1991 printing of The Making of
   Star Trek, by Stephen E. Whitfield and Gene Roddenberry:
 

"And then the Lord did look down upon his chosen studio, and he saw that it
was good.  And from this worthy vessel did he make to be made his sacred Star
Trek, and in the producership thereof did he place a holy man by the name of
Eugene, son of Bluegene, son of Hygene.  And Eugene did begat April, and Pike,
and Kirk, who in turn begat David, upon which we shall not further dwell.
 
But the April was not good, and the Lord did turn his face from him, and the
Eugene did sacrifice him upon the altar of superior drama.

And the Beast who dwelt in the network of sodom and national broadcasting did
look down upon the Pike, and did say unto Eugene, 'For he is too cerebral, and
the audience will get him not.'  And when the Eugene did go to reshoot, he
foundeth that the the Pike had been taken to a new movie and making himself
available he could not.  And so Eugene did turn to the Kirk, and they didst
make the Star Trek together.
 
So endeth the first lesson."