While I appreciate the sentiment behind the idea that a first date has gone spectacularly if both parties are unaware of the other's siblings, I must respectfully disagree. To me, a successful first date is one where both parties leave feeling a sense of connection, understanding and chemistry. While inside jokes can be an important part of building a connection, they should not be at the expense of gathering important information about one another. Therefore, a first date should involve a meaningful conversation, including asking each other questions in order to learn more about one another, such as how many siblings each has. Additionally, the more a couple knows about each other, the more they can build a stronger relationship on the basis of that knowledge. Therefore, a first date where neither one knows how many siblings the other has is not necessarily a sign of a successful date.