The Cameroon-born player's age has been questioned by some, but speaking to Dortmund's official website in April, his father Joseph said there was no reason to doubt it.
"Right after his birth, I registered him with the German consulate in Yaounde [Cameroon's capital]," Moukoko Sr., who has been living in Germany since the 1990s, said. "The boy can't be older because his mum, Marie, is only 28."
..from espn