HELP! Gender reveal!!

I want to do something cute for a gender reveal to the dad's parents, they already have 2 grandsons and I'm begging for a girl so I wanted to do something cute talking about it being the first granddaughter. Was thinking a onsie in a little box but I wanted some help thinking of something to write as a note making a big deal about it being the granddaughter. I don't know it's a girl yet just hoping, so suggestions about it being the 3rd grandson help too!! Thank you!!!!