The 86-year-old and Harris, 26, married in a small ceremony at the Playboy Mansion in Hollywood on New Year's Eve, reported Daily Star.
"Crystal is desperate to have Hugh's baby. She thinks it would be the most beautiful way imaginable to show him how much she really loves him.
"Hef is insisting he's still man enough for the job, telling family and friends at the wedding he's still up for it. He wants to show the world that age shouldn't stop you doing anything," a source said.
Hefner was previously married to Mildred Williams and Kimberley Conrad and has two children with each of his ex-wives.
It is the first marriage for Harris, who recently opened a lingerie store, Femme Fatale, in Studio City, California.
