May,
I think it's difficult to keep the gender a secret till delivery. Your ILs will never believe that you and HB don't know.
but you can try... if your ILs ask, just ask your HB to retort back to you ILs that you and HB purposely told your gynae not to say cos it does not matter to both of you whether it's boy or girl and tell your ILs sarcastically that somemore if it's a girl, sure get black faces from them. What for find out???
But seriously, you and HB are proud of your kids, regardless of the gender. Even if your ILs ask, there's no shame in telling them. If they are unhappy, that's their own business. I know it's easy for us to say this since we are not the ones having to deal with such ILs... just don't let them get to you.
Anyway, I'm sure your ILs will learn to love and dote on your #2 in no time after she's borned. After all, she's their grandchild.
I mean, your ILs dote on Jamie right?
So don't feel bad about this. Let them say and do what they want. It's not something you can control.
Rachel / Belinda,
I think your ILs are just showing their appreciation. Sure, it's not their kids, but your kids are their grandchildren. So it's still flesh and blood in that sense. My ILs didn't say thank you to me... hahah, though I think I would feel pretty weird if they do too.