Newsweek obtained previously unreleased audio from a 2005 recording of The Howard Stern Show, where Trump was a guest that website Factbase has since made public.
Stern asked Trump during the show "Did Donald Jr... There was a rumour that Donald Jr. And Ivanka tried to bump off a child."
Trump responded with his youngest daughter Tiffany's name, saying that he has a "great child in Tiffany".
"But fact is every time you have a child it's 15, 20, 25 percent less of all the money.
"So, I guess, you know, maybe they're not thrilled."
Trump seemed to talk around the question but Newsweek says it's not the only time Trump has slighted his youngest daughter.
On election day, Trump said he was proud of Donald Jr. Eric and Ivanka then added: "To a lesser extent 'cause she just got out of school, out of college—but, uh, Tiffany, who has also been so terrific."
Tiffany is Trump's daughter from his second marriage to Marla Maples and she spent most of her childhood with her mother in California.