Tennis Player Kim Clijsters Gives Birth to Son

"Jack Leon Lynch is born! Born at 7:06 p.m. tonight and we are both doing well," the new mom, who gave birth in Belgium, writes. "His big sister, mama and daddy are very proud and happy!"

Baby boy joins the couple's daughter Jada Ellie, 5½.

Clijsters, who retired from the sport after competing in the 2012 U.S. Open, announced her pregnancy in February.