Sherlock's not asexual. He just chooses to abstain. He was also deeply infatuated with Irene (as said by both Benedict and Moftiss) and that, coupled with his remarks and behaviour in The Sign of Three seem to suggest that he's straight. That being said, I think Sherlock's sexuality could be fluid. Truly, I think he's mostly sapiosexual.

Good question. In the canon, if I'm not mistaken, Sherlock Holmes never kills anyone. However, I find it difficult to believe that this particular incarnation never killed a man. I mean, even at the end of ASiB he's slaying people left and right with his scimitar to save Irene.  Or during his two years "holiday", as Mycroft put it, it's unlikely he never had to defend himself... with a gun. 

However, I do think this is the first time he killed in cold-blood. Sherlock basically executed him. And I don't think he'll be particularly affected by it, he despised CAM with all his heart. 

He used morphine in the canon (and cocaine), not opium.

I think you're reading a little bit too much into it lil. The show does comedy sketches, at least, it did this season (not just the ex boyfriend scene but also the scene with the kid, for example; or the lapstick comedy in the drunk John&Sherlock sequence). To extrapolate from that scene that Mary is cheating on John is making a wild unsubstantiated leap of logic.

You just don't go around trying to kill people to save your relationship with a man you're cheating on anyways... Mary absolutely adores John, I think we can be almost certain about that (yes, there's the possibility that it's all a ruse/she's working for someone/whatever and I'm not ruling it out but I think it's quite unlikely). When Sherlock tells them the news I don't see anything but some reasonable panic mixed with excitement and peppered with shock, which is something I think most couples go through the moment they learn there's an unexpected baby on the way 

Also making the baby not John's would be such a gargantuan cop-out I wouldn't be able to cope LOL Way to write themselves out of a sticky situation. I trust the writers to be way more intelligent than that. The fact remains that the baby is the real crux of the problem here. Mary could be dispatched in a number of ways, but baby girl Watson? I can't see them killing a baby - John's baby - on the show, and I actually don't even want to see them go down that road. It would absolutely break John. Not that losing only Mary wouldn't - it's obvious he's head over heels in love with her - but losing both Mary and his baby daughter would be just a hot double serving of tragedy and heartbreak and I fear the tone of the show would be altered forever. 

You can determine the gender at about 18-20 weeks. So they either knew the sex beforehand but weren't telling anybody before the birth (in which case John disclosed a sweet piece of information to Sherlock) or they found out between the shooting at Appledore and Sherlock's departure. I think it's the former, it would be weird for a couple of expectant parents to ask for the gender just a few weeks before the birth itself. Usually people find out either the very moment they can have the result or at birth.

Actually, I'm taking the sickly part from Baring-Gould's biography of Sherlock Holmes. It's not really canon, but he was a preminent Sherlockian scholar and Moftiss seem to be aknowledging his work (the "other brother", Sherlock's full name). Also, the fact that he wore his cardigan all buttoned up. I was a sick child myself and my parents always insisted that I wear multiple layers with a top cardigan buttoned up to my neck. I think that's why I made the association 

Willow wrote:

Incidentally, I don't think there is much evidence to support the claim that both Sherlock and John are emotionally-stunted, but that's a different topic. I look forward to you starting a thread about it
 

Ohhh, I'll do it! :D

They're just friends. 

Chibi?

^I'm with you, I don't think John is being difficult to read per se. It's just that two years have elapsed and he's a different person than the John we knew from seasons I and II. He's got a lot more going on in his life, a full time job, a wife with a past and a kid on the way and he's been hardened by grief (not that he was that good at expressing his feelings before). Basically nothing is ever in his control and that bothers him, nothing's turned out the way it was supposed to do; his best friend has murdered someone for him. To paraphrase Sherlock, "what the hell are you supposed to say to that'?" He probably feels overwhelmed and guilty about it.