* it'll be a girl because everybody I know has had girls recently
* it'll be a boy because everybody I know has had girls recently
* it'll be a girl because you get more morning sickness with girls
* it'll be a boy because of the position of the bump
* it'll be a girl because of the position of the bump
* it'll be a boy because 'boy' scores more in Scrabble
So that's two answers from people who don't understand probability, three answers which sound to me more like superstition than something which is backed up by any actual research (though I'm happy to be proved wrong), and invisiblechoir being silly. :-)
Two of my colleagues have a bet with each other about which it will be. I don't stand to gain any money from this bet myself, unfortunately. On the other hand, since earlier today one of them couldn't remember which way he'd bet (he'd decided at the time by tossing a coin) I don't think he's taking it that seriously. The other one asked me if I'd tried putting a toad on the bump to predict the baby's sex (I'm not sure quite what one is meant to do with the toad, or wait for the toad to do...?), so I guess he's not wholly serious either. I hope.
I confess I'm keen to know the answer, not least because referring to it as "it" feels awkward. Yes, I may get flamed for Gender Fail, but I'm afraid we're just not progressive enough to try to bring the child up without any awareness of the existence of sex or gender, and let's face it, there's a staggeringly high chance that it will be biologically male or female. Also, I'm going to have at least one more scan after tomorrow's, and I don't want to have to "look away from the screen now" for fear of spoiling the result -- I want to see what's going on! Basically, in most cases I will generally choose the path of More Information.
We also want to start thinking more seriously about names, and it'd be useful to narrow down the choices a bit. Other tactics for narrowing-down include: avoiding names with ambiguous spellings; avoiding extremely long names; avoiding alliteration; and summarily rejecting every single name that appears on this site. So that's a big 'no' to Breckin, Maxigan, Skyler Alexander, Cam'ron, and Kaytaquana. Suddenly, my silly suggestion of naming my child Badger doesn't seem all that ridiculous...