I suggest that if the fetus turns out to be male, we all start referring to it as Merlin so that Alicorn's husband has no choice but to bow to the will of the crowd.
Did you miss the thing where Alicorn wants potentially-him to be named Merlin (if male) and Mike is vaguely against it? I think that's been discussed much more on tumblr than here.
Mike currently expects that in order to be able to name the fetus promptly upon learning its sex he will acede at that time to the name, he just refuses to update in advance.