50/50 chance as not finding out the sex.
DB and DSIL have decided it's very unlikely they will ever have children. But in a conversation years ago, they did say that if they were to have a girl they would use our Grandma's name as their daughters middle name.
We have a girl, who has our other grandmother's name as her middle name ... are you still with me?
! Therefore if we have another girl we'd like to use the other Grandmother name as it seems a fitting thing to do.
So ... for those still with me. Do I ask my brother and DSIL if they mind us using it?
My DH doesn't seem to think it's an issue as they might not have kids anyway, whereas I don't see any harm in asking as it's polite and the likelihood of them saying no is slim. Plus they won't get the 'oh - we said we'd use that name' feeling I know upsets so many people.
Here's where we have a boy and they decide it's a definite no on kids! 