Is this their father?
He's their son.
Is this their mother?
This is their mother.
Are these their parents?
These are their children.
Are these their children?
These are their parents.
Is this Bart's sister?
This is Bart's sister.
Is this Lisa's mother?
This is Lisa's brother.
How is Homer related to Bart?
He's Bart's father.
How are Homer and Margie related to Lisa?
They're Lisa's parents.
How are Lisa and Bart related to Homer?
They're Homer's children.
