[JohnnaMJH]

Well, it isn't mentioned, but I though it was interesting that in the same story, it was referred to in two different ways:

Henri Behar, who moderates Cannes’ news conferences, read a message from Pitt, who has been in Namibia with his “Mr. & Mrs. Smith” co-star, Angelina Jolie, awaiting the birth of the couple’s first child.

“With the imminent arrival of the newest addition to our family, I am unable to join Alejandro, Cate, Gael and the rest of the cast and crew in introducing” his new film, “Babel,” the 42-year-old actor said in the message.

So, as I read, I'm first thinking, what do you mean their first child, they have TWO already???

But Pitt himself used the phrase 'newest addition to our family" which shows he gets it.