In one episode, the phrase "mating season" is used in a scientific context.
Both "The Robot Revolution" and "The Buried Spaceship" feature Slim expressing his love to Marla, Raeburn's secretary, who is also Venusian.
As the programme dates back to 1962, its ideology often reflects sexist attitudes to women at the time. For instance, "For a woman she doesn't talk much!" (several episodes), "Looking lonely as ever and talking nonsense just about makes her a normal woman!" ("Destruction by Sound"), etc. Modern viewers may be offended by this.