"Journey To Babel" was inspired by D.C. Fontana’s interest in Spock’s parents after she and other writers had left little clues about them throughout the first season’s scripts. She told Star Trek: The Magazine: “The idea really came out of the line toward the end of ‘This Side of Paradise’, where Spock says, ‘My mother was a school teacher, my father was an ambassador.’”

"I sat down and created two characters, emphasizing the triangular relationship – the rift between Sarek and Spock, with Amanda positioned in the middle," Fontana added.

(via bestyeomaninthefleet)