Bromance

Well besides that fact that your bodies literally try to prevent you from doing it. In any way

Some people end up with disabilities anyway, so you might as well go for it. Incest is wincest!

At least someone saw the underlying comedy in my comment.

Not necessarily true. That only happens when they're raised together, not apart.
Sexual attraction between siblings and parents and children that we're raised apart and didn't meet until adulthood is actually more common than you think as the part of your brain that triggers your revulsion response with family members doesn't connect to the people you weren't raised with.