Sir Arthur Conan Doyle thought they should be looking for a woman. DNA samples taken from the back of a stamp on one of the letters believed to actually have been written by the Ripper, suggest he may have been right.
I have always thought that the Ripper was in fact a female member of the Royal Family in male attire using one of the carriages without the coat of arms from the Royal Mews...doing so out of a twisted sense of revenge for some nameless prostitute having infected the Duke of Clarence
What were the points about the case that lead him to suggest seeking a woman?