"Shouldn't" implies there's a universal way things should be. There isn't a universal "way things should be" because ultimately the "way things should be" is subjective and determined by an individual person. From an objective point of view, there is no "way things should be", it's just "the way things are."
I know? This is demonstrated by the fact people are gay. But in science its not supposed to happen so stop loving making it normal cause it's not.
"Science" does not determine what should or should not happen. Just because something does not function biologically does not make it not normal or unnature.