 CHAR: At the beginning of this episode, Kirk, Spock, and McCoy are  standing on ceremony in the transporter room to welcome Sarek, the  Vulcan ambassador, and his human wife. After theyve been received,  Kirk invites Spock to take a few hours to beam down to Vulcan and  visit his parents. To Kirks visible astonishment, Spock replies,  "Ambassador Sarek and his wife ARE my parents". Surely Captain Kirk  would already have enough information about his second