Haw. Rev. Stat. § 572B-3: [ §572B-3] Civil unions void; when.

[ §572B-3] Civil unions void; when. A civil union shall be void between the following persons: parent and child, grandparent and grandchild, two siblings, aunt and nephew, aunt and niece, uncle and nephew, uncle and niece, and persons who stand in relation to each other as ancestor and descendant of any degree whatsoever.