As of my knowledge cutoff date in 2023, Tracer, also known as Lena Oxton, is a fictional character from Blizzard Entertainment's video game "Overwatch." She is a time-jumping adventurer and an irrepressible force for good. In the official "Overwatch" lore, Tracer does not have any children or grandchildren. The backstory provided by Blizzard Entertainment has not included any personal details of that nature. Tracer's known relationships are mainly with her fellow Overwatch teammates, and her girlfriend, Emily, who was shown in the "Overwatch" digital comic titled "Reflections." Remember, as a fictional character, Tracer's story is subject to the imagination of the game's writers and any extended universe materials they may produce. Unless Blizzard Entertainment decides to add to Tracer's backstory or the game's lore, she does not have descendants in the current narrative.