Actually, the child referenced is Maya Soetoro, Barack's half-sister born in Indonesia. You have to look very carefully at the 1980 divorce papers to notice that Barack is referenced, but not by name: "1 child above 18 still dependent on the parties for education.".
He had just started college at Occidental. That is why those records are so important -- and why Obama's (I'm sorry, Barry Soetoro's) legal team is blocking the Occidental College records from being released to Gary Kreep at the U.S. Justice Foundation and the Public: