Bond, how annoying about your in laws. Just tell them and let them suck it up. If you want to tell people, that's your right.
We found out the sex because I'm impatient, but also because I didn't want neutral stuff for bub. We have told DH's mum what we are having, she's gone out and bought stuff for bub but said she bought all neutral because we don't know for sure what we are having. 2 scans have said girl, so we're happy with that, but apparently she's not.
Then she asked if I was going to follow her family tradition and give bub a strange name. Just cos she and her daughter thought it was a good idea, doesn't mean I should have to. DH and I have come up with a name we love, and it's not strange.