 When story editor D.C. Fontana (qv) was writing her episode  "Yesteryear," she ran into opposition from the network executives  when they learned her story would have Spocks beloved pet mortally  wounded and requiring euthanasia. The executives were concerned that  it would upset young viewers and insisted that the pet be allowed to  live. Gene Roddenberry (qv) supported Fontana and reassured the  management that she would handle the story appropriately. As it  turns out, there were never any complaints about the episode and the  story is considered the finest of the series.