Board Thread:Arrow discussions/@comment-9346948-20160324010312/@comment-3423279-20160324184936

SeanWheeler wrote: Even when Barry is adopted, it still feels weird how he's destined to marry his sister. I suppose from our perspective, but Barry never considered Iris as a sister.

If he did say "I want to be in a relationship with my sister." that would be a bit creepy, but Barry has only ever shown that he views Iris as the girl he likes and his best friend, possibly more, not a sibling.