Sherlock: 7 Things We Can Look Forward To In Season 4

2. John & Mary's Daughter

Now we really are going beyond canon. After the reveal of Mary's pregnancy in The Sign of Three, in His Last Vow, John reveals that the baby is a girl... a girl who will not be named after Sherlock, to Sherlock's chagrin. Perhaps a variation? Sherlly? Hmm, maybe not. Whatever the case, bringing a baby into the mix has never boded well for other shows; it will be interesting to see how the writers handle this particular plot point. With a father as loyal and courageous as John and a mother as intelligent and formidable as Mary, there's no doubt that this will be one amazing child. As for Sherlock's probable role in her upbringing, we've seen that Sherlock can, in fact, get along well with children, as can be seen in his delightful interaction with Archie in The Sign of Three. What's worrying about this particular development is the fact that the addition of a baby to the Watson family will also add another "pressure point" for John, which may be dangerous with Moriarty's return. Also, the fact that Mary Morstan dies in the original Conan Doyle stories (though, granted, between The Final Problem and The Adventure of the Empty House, which the show has already passed with The Reichenbach Fall and The Empty Hearse) is something I think should be kept in mind should the show return to a darker tone reminiscent of His Last Vow.