He's not my brother. He's my son.
5 seconds sound clip from the Billy Madison movie soundboard.
You can hear this line at 00:24:20 in the Blu-ray version of the movie.
Quote context
[...]
- Mortal Kombat on Sega Genesis is the best video game ever.
- I disagree. It's a very good game, but I think Donkey Kong is the best game ever.
- You know somethin'? You suck!
- Hey! That's very nice of you to pick up your little brother here at school.
- He's not my brother. He's my son.
- Mom, that's Billy. He's in my class. I heard he's retarded or something.
- Your son's got a very creative mind. Maybe someday he'll make Mommy and Daddy a lot of money.
- Daddy's in prison, and he won't be home for a long time.
[...]