I remember when my aunt was pregnant with her second child. We were visiting their house for the day, and during lunch, their son Bobby, who was about 2 1/2 or 3 years old, was looking at Aunt Francie's stomach with fascination while he was eating his hot dog. Finally, he pointed and asked her "Is the baby in there?" (a question he'd already asked many times, apparently). When she assured him that the baby was there, he leaned over with some of his hot dog, held it two inches from her stomach, and then said, "Are you hungry, baby?"
It was sooo adorable! I mentioned it to him when I last saw him at my sister's wedding. He did the usual oh-god-not-another-baby-story that most men in their mid-30s will do at that point.