Donald Trump, Jr. and his model wife Vanessa Haydon Trump have welcomed their fourth child. On Sunday, Oct. 21 he made the announcement on Twitter. "It's a BOY!!!" Trump, Jr. tweeted. He also added that his wife and child are doing well. "It's a BOY!!! @MrsVanessaTrump and baby are doing great," he tweeted. The couple's new bundle of joy is the latest addition to their first three children: Tristan Milos, 1, Donnie John III, 3½, and Kai Madison, 5.