I do understand the wondering, if you've not ruled out a third child anyway. I have two DS, one 3 and one a little baby. I would have liked a girl, but had I had two DD's, I think I probably would have liked a boy. It's the wondering of what a child the opposite sex would be like. Saying that it's early days, my DS' don't really look alike so they will probably be completely different!
I also don't feel "done" though, mainly because I've loved having a little baby again so much, I feel I want to do it again! And if I had a third, I would secretly have a preference for a girl. But if I had a boy, that would be that. I would adore him in the same way I adore my two DS, and our family would be complete.
where would it stop for you? I would NEVER have 4 children, whereas even pre DC, I definitely wondered about having 3, as I'm one of 2 and always thought it would've been nice to have had another sibling. So if you just want to give yourself one more "chance", then go for it. But if you think you would then want a 4th, then a 5th, if you keep having boys, I think it's safer to stick at 2!
And if it's any consolation, DH is one of three, the youngest being a girl. I don't think MIL was trying for a girl, as they have implied that SIL was an accident, but oh my gosh SIL is so hugely favoured by MIL. It's sickening. They're all adults now, BIL and my DH are lovely men, happily married with families and in good jobs. SIL is a spoilt overgrown child, unhappy because she feels the world owes her something. She mainly spends time with MIL and her mates, and doesn't have much of a life of her own. It's sad and I always think it's a reflection of how she was brought up.