Yeshiva Bochurs first date

A Yeshiva Bocher (young man) is about to go on his first date, and is nervous about what to talk about. He asks his Rabbi for advice.
The Rabbi replies: "My son, there are three subjects that always work. These are food, family, and philosophy."
The boy picks up his date and they go to a hotel lobby to talk. They stare at each other for a long time, as the boy's nervousness builds.
He remembers his Rabbi's advice, and chooses the first topic.
He asks the girl: "Do you like spinach?" She says "No," and the silence returns.
After a few more uncomfortable minutes, the boy thinks of his Rabbi's suggestion and turns to the second item on the list. He asks, "Do you have a brother?"
Again, the girl says "No" and there is silence once again.
The boy then plays his last card. He thinks of his Rabbi's advice and asks the girl the following question:
"If you had a brother, would he like spinach?"