Seems all I ever ask on these boards is baby related, sorry about that

I gave birth last Saturday to a beautiful baby girl.
Now my husband is from a very large family: his grandmother, who is a really sweet person, had 9 kids. Of those 9, most of the boys ended up getting daughters, with the exception of a few. So while she has a lot of descendants, only three of her male grandchildren carry her husbands name. And of those three, my husband is the oldest.
When we went over to her place to tell her we were pregnant, the first thing she said to me was "and if it could only be a boy, that would mean the world to me." I bit my tongue, and she hastily added "but of course a girl would be lovely as well!"
Now I can see why this would be important to her, so I didn't make a fuss.
After the delivery my husband called her and told her it was a girl. I didn't hear the conversation, but he told me that she said it was a shame it wasn't a boy. Again, I tried not to let it get to me, after all she didn't say it right to my face this time.
A day later, she came to visit us at the hospital. Our baby was staying in the locked off area because of an infection, so only us as parents, and grandparents under supervision were allowed in. She seemed very happy, so my husband asked her if she wanted to go in and hold her. She sits down, and I hand her the baby (no worries there, she raised 9 of her own after all).
And the first, the very first thing out of her mouth is "and now all you need is a brother, don't you?"
... seriously? That's the very first thing you have to say when you're holding your newest great-grandchild? That she's not good enough?
It's upsetting me, but I really don't know how to respond to it. My husband understands where I'm coming from, but the general family consensus seems to be 'she doesn't mean it in a bad way, hers is a different generation, don't let it get to you'.
Part of me just really wants to go "oh no, we're done, one child is enough" the next time she brings up the brother bit again, but I suppose that would be e-Hell stuff

But yeah, what's a polite but firm way of putting an end to this before baby gets old enough to understand the undercurrent here? I can see where she had a preference, but I really do not want her voicing that in front of my kid. She has made her point, and now I would really like for her to shut up about it.