"Jeremy received news before yesterday's match that the birth was imminent," said the team doctor, Brahim Hacene, in a statement from the Belgian federation.
"As he had already been receiving appropriate medical treatment for several days, he was able to fly without medical risk to be with his family during this very special moment.
"He was accompanied by my colleague, Dr. Brecht De Coninck. Everything went perfectly, and the mother, father, and baby are all doing wonderfully. Jeremy will rejoin the squad tomorrow (Tuesday) evening in Seattle," Hacene added.
Doku missed Belgium's 1-1 draw with Iran in Los Angeles on Sunday, having been ruled out on the eve of the game by coach Rudi Garcia.
"He can't play, and so we'll be playing without him," Garcia had said at the pre-match news conference, adding that Doku was still recovering from illness. "I knew since Friday that he won't be playing.
"I don't want to get players to play if they're not medically up for the game. I can get players to play even if they're not 100 percent physically, but 100 percent medically is more important."
Belgium, who have drawn their opening two games at the World Cup against Egypt and Iran, are next up against New Zealand in Vancouver on Friday in their final Group G fixture.
FIFA World Cup 2026
The 2026 World Cup is taking place from June 11th to July 19th in the United States, Canada and Mexico. The tournament features 48 national teams and is played at 16 modern stadiums.
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