"A French lesbian had asked if [my ex boyfriend and I] would be sperm donors," Alexander revealed on The Tyra Banks Show on Tuesday. "So we did a little test tube."
Though his ex is the biological father of 7-year-old Boris, in his new book, Follow the Model, Alexander said, "We are all actively involved in rearing Boris, and the experience has enriched my life beyond imagination."
"He's an incredibly smart child. He was toilet trained at a year and three months. He refuses to drink out of plastic and will use only glass," said Alexander. "He insists on wearing nice shoes. I think somehow my fashion genes must have slipped in there."