A Starfleet brat was a term for the child of one or more individuals who were officers in Starfleet. "Starfleet brats" often grew up on starships or outposts far from home because of their parents' assignments.
In 2375, when "Valerie Archer" told Chakotay that both her parents had been starship officers, he referred to her as a Starfleet brat. She then described herself as "Bratty as they come." (VOY: "In the Flesh")