No need to talk to any body, it is natural. They have been passed through those  stage.
If they heard , no big deal at least they are satisfied that thier JOI is not gay as the name appears.

They will go home with a hope that soon they will be grandparents and do not disappoint them, keep up good karma . You may take the advise of bairagikailo, put some clothes in her mouth as you have visitors in your home. Other wise do not worry, let her be happy and let her be enjoy too.