Thanks to the wonders of modern medical technology, we can confirm that Brit Junior is a girl. Unless she is a boy.
The only thing we can say for definite is that it's definitely not definitely a boy. It may still be a boy, but only possibly, since although you can get positive confirmation of boyness, you can't get guaranteed confirmation of girlness. All we got was a lack of positive confirmation of a boy. So it's probably a girl, unless it isn't.
So that's good to know.