You need to think deeper about this. The button says that you'll share the same parents, but not necessarily the same biological parents. If the man/woman of your dreams is adopted, then it technically isn't incest, at least to the point where you'll be producing fucked up inbred babies. So frankly you'll have to do a lot better than that to stop me from slamming the fuck out of that button. Besides, even if it would be morally dubious to start a relationship with her bringing Sana back might at least get her to stream again. So worth it either way.