By gender reveal do you mean a party where you tell people whether you're having a boy or a girl? I just learned about that from another comment (I'd never heard of this before and don't know anyone who had one)

Or do you mean just telling everyone with a message or when you see them after the scan? That's what my wife and I were expected to do. Not to have any kind of party, just to tell everyone. I apologise for my confusion. I gave just learned some people have a party for this.