Citizenship

I overheard an argument between 2 boys at the water fountain on the playground:
1st Boy:You are Korean
2nd Boy:I am not. I am American.
1st Boy: No, you are Korean because your dad is Korean.
2nd Boy: No. My mum is American. My sister was born in America. I was born in America. I am American.
1st Boy: Well, that doesn't make you American.
(At this point, I nearly laughed out loud. What does make you American, then?)
1st Boy: Don't you want to be Korean?
2nd Boy: No.
1st boy goes off in offended huff.