Retired tennis champion Ash Barty on Tuesday announced the birth of her first child. The former No. 1 player, who retired just over 15 months ago, revealed on social media that she and husband Garry Kissick had welcomed a baby boy. “Our beautiful boy. Welcome to the world, Hayden!” the Australian wrote on Instagram alongside a photo of the newborn. The three-time Grand Slam champion who spent more than two consecutive years at No. 1 in the rankings retired at the age of