Field help: 1 = biological child / adopted child, 2 = foster child, 3 = grandchild / stepchild Specify here the child relationship to the taxpayer: Biological child/adopted child: Biological or adopted child with legal parent-child relationship. Foster child: Child in your household without adoption, but with a family-like relationship. Grandchild / stepchild (no parent-child relationship): Grandchild or stepchild without parent-child relationship.