Given the everlasting popularity of the Sherlock Holmes character, the recent portrayals of an overlooked Holmes sister have led audiences to search Sir Arthur Conan Doyle's original source material to determine whether she's real. Inspired by a real-life colleague of his, Doctor Bell of Edinburgh, for his uncanny abilities to diagnose patients upon first impressions, Doyle explained, in an audio recording of an interview from 1930, his desire for Sherlock Holmes to depict stories "where the hero would treat crime as Dr. Bell treated disease and where science would take the place of chance." (via bl.uk)

https://screenrant.com/does-sherlock-holmes-have-sister-original-canon/