Ugh, she annoys me and i don't even know her. I would be quite offended by her comments, she really should know her audience,she seems a little clueless. However, she will probably be insufferable either way. If she gets a girl she will be so in your face gushing about it and if it is boy she will be all sad and vent to you about how unfair it all is. I don't really know what you can do about it other than try to change the subject and talk about anything other than gender to her. Can you avoid her?
I totally understand where you are coming from. I also understand wanting a particular gender ( and it doesn't bother me on this board) but I admit that in real life it bugs the crap out of me when people have such strong preferences especially if it the first kid or if they already have that gender.