Of all the things she could have said, that was certainly the last thing that had come to mind. He stared at her, to her belly to her face.

"And... you came to me?" he clearly didn't understand. Was it the Doctor's? Someone else's? "Surely you're not suggesting it's mine?" That was so outside the realm of possibility, he looked flabbergasted. Perhaps this was the reaction she'd feared? But it was just so impossible.

"I'm sterile, River. No Immortal has ever had children."