You must not have sexual relations with your son’s daughter or your daughter’s daughter, for that would shame your family.
KJV
The nakedness of thy son’s daughter, or of thy daughter’s daughter, [even] their nakedness thou shalt not uncover: for theirs [is] thine own nakedness.
ASV
The nakedness of thy son’s daughter, or of thy daughter’s daughter, even their nakedness thou shalt not uncover: for theirs is thine own nakedness.