Are Tegan and Nickson actually related?

Mai Morning Crew 16/12/2019

Tegan and Nickson have been scrolling through comments and for some reason this question keeps popping up: Are Tegan and Nickson siblings?

Sad to say, they may look like two peas in a pod but they are not siblings. They aren't related. The only main thing they have in common is this--the fact they both reckon they are good-looking half-castes. 

^ Fact.