The 43-year-old producer shared the news with an Instagram post on Saturday, Berlanti announced his new arrival. "It is with much pride and love that I introduce to the world my son, Caleb Gene Berlanti," he wrote.
The post was accompanied by a collage of photos of the newborn with Berlanti and his boyfriend, former pro-soccer player, Robbie Rogers.
"Achieving this dream would not have been possible without the love and support of my wonderful family and surrogate, incredible boyfriend, amazing friends and co-workers that encouraged me and helped me on this remarkable journey," Berlanti said.
"Check back in approximately 25-30 years for the tell-all about how I screwed it all up," he joked. "Until then apologies for the over posting of baby photos. My heart is full forever."
Berlanti is the producer behind a string of television hits including Dawson's Creek, Arrow, The Flash and Legends of Tomorrow. He has been in a relationship with Rogers, a former LA Galaxy player, since 2013. Rogers, 28, was the first openly gay player in a major U.S. sports league.
Caleb is Berlanti's first child.
Find out who else is expecting babies in 2016 in this video.