This is definitely a Victorian book since the sex is pretty much nonexistent here. In fact, our two main characters never even have serious love interests (and Holmes's fake engagement in "Charles Augustus Milverton" doesn't count). But, in true Victorian fashion, there are hints of sex. Nothing is stated outright, though. A lot of the crimes Holmes encounters involve love, jealousy, secret affairs, stalking, and abusive relationships. But interestingly, Holmes never actually deals with any sort of sexual crime; that sort crime certainly existed in Victorian England, but it was not discussed openly. With all its omission or repression of sex, The Return of Sherlock Holmes is definitely a product of its era.