News Kourtney Kardashian Welcomes Third Child with Scott Disick By Rosalyn Oshmyansky 2:08 PM PST, December 14, 2014 Getty Images Keeping Up With the Kardashians' Kourtney Kardashian gave birth to a baby boy Sunday with Scott Disick,Us Weekly confirms.The couple now have three children, and their new addition shares a birthday with their son Mason, 5.Kourtney, 35, posted a message saying she is "blessed and honored" to be Mason's mommy today. View this post on InstagramHappy birthday to the coolest little boy in the entire world. You teach me so much every single day and changed my universe the second I met you. You have taught me what life is all about and I am truly blessed and honored to be your mommy.A post shared by Kourtney Kardashian (@kourtneykardash) on Dec 14, 2014 at 12:25pm PSTPHOTOS: Kourtney and More Celebs Who Posed Nude While PregnantKourtney and Scott also have a daughter Penelope, 2.Just last week, Kourtney revealed she was having a boy on her reality show Kourtney and Khloe Take The Hamptons. NEWS: The Kardashians Are Clothes Sharing SistersShe said, "I am so happy we're having a boy," Kourtney says. "It's going to be perfect for our family."Congrats Kourtney and Scott!Kourtney's sister Kim is trying for another baby. See what she has to say about giving North West a sibling below.