Why does one daughter and one son have different family names?
One thing is DOES point out, though. Teenagers have sex with each other nowadays and think nothing of it. What they don't realize is that there is a strong psychological bond created, and it affects some kids more than others. We've seen a lot of violence among teens created by this psychological bond, when they realize that they've been betrayed by someone with whom they had sex, and thought the feelings of exclusivity that they had, because of that bond, were mutual, and realized that they weren't.