"What Are Little Girls Made Of?" is episode seven of the first season of the science fiction television series, Star Trek. It was first broadcast October 20, 1966, and repeated, two months later, on December 22, the first episode of the series to be repeated on NBC. It was written by Robert Bloch and directed by James Goldstone. The title of the episode is taken from the fourth line of the 19th century nursery rhyme, "What Are Little Boys Made Of?." In the plot, Nurse Chapel searches for her long lost fiancé, and uncovers his secret plan for galactic conquest.