That's what I was thinking. The question specifically asks about MY relationship TO this relative. And MY relationship TO my mother or father is CHILD (NOT PARENT) because I am their child.
The only thing that confuses me is that the next screen shows my mother or father name with CHILD under it. When, say, in Part 4 (Information about Beneficiary's family), where I list all the members of my parents' family (including myself), on the next screen I see the Beneficiary's spouse with SPOUSE word under it and the Beneficiary's child with the word CHILD under it.
I guess I'll leave CHILD as I did myself and as you suggested.
Thanks!