We chatted and joked, and slowly our talk turned to her pregnancy. I was about three drinks in, and it suddenly hit me that I was talking to the woman I had knocked up. I had so thoroughly thought of this child as being Alena and Kate's that I had almost forgotten. There's a fun sense of power to the thought that all the changes a person's body are going through are because of you. Because you fucked them, and came in them.

"So," I said, "which time do you think it was? On the table? Or that time on the couch while we were watching Kate put on a...