Thanks all. I have a story idea where it is later revealed, in part, that the person you've fallen in love with turns out to be your father's half-sister or sister-in-law. I don't want to over-complicate it, and yet I don't want to turn off some one who might be leary of incestuous relations. Though it isn't the primary theme of the story in any event.
The setting would be a quasi-fantasy historical setting where one character is a princess and presumptive heir to the throne, as there are no other male heirs. The king was widowed not long after the birth of their daughter (the princess). The late queen though had a sister, one who was subsequently banished from court.
Of course, that woman would be the princess' aunt. That relation might be too close for comfort for some. So I was trying to think of a way to work it out they didn't share blood, and thus any potential writer might be okay with it. Just trying to keep it simple too. Also, I don't want this wrinkle to be revealed until later in the story, thus I need to be fairly comfortable a potential writer won't be unduly made uncomfortable with the idea.
I could find someone who I knew was okay with familial relations, but not reveal to them ahead of time of this wrinkle. Hmmm.