My mother in-law was like this for both my successful pregnancies.. She already has 5 grandchildren (well now 6, going on 7 when including our 2), and 2 of those are girls, 5 are boys, so it's not like she is missing out of anything.
But when we had our first son she was very verbal about her hopes for it being a girl, which he wasn't. She did exactly the same thing again this time. Funny thing was when I lightly 'jested' to her saying "Oh well Judy, you'll just have to get over it being a boy. No more girls for you", she got all defensive and started saying she didn't mind that it was a boy lol.
My hubbys 2 niece's were also hoping for a girl, but they're little girks themselves and I think that's half to be expected (spesh when they're surrounded by boy cousins left, right and centre).
Luckily noone else has said anything rude to us, as it does get frustrating at times. I would certainly never ask anyone if they were hoping for the opposite gender. I'd only ever discuss gender/disappointment if it was something they brought up themselves.