The journalist explained that Vanderbilt said she'd serve as a surrogate for Cooper, should he want to have a baby. "I finally said to her, I was like, 'Mom, I love you, but even for you ...

COOPER: “To me, it’s like baby pigeons.” COLBERT: “What’s baby pigeons?” COOPER: “It’s baby pigeons. They exist. I haven’t seen them [but] they exist.” Watch above via CBS.