OK, I'll concede the "small minority equals abnormal", but what about "abnormal equals imperfect, not according to intended use"? Riding a bike backwards, sitting on the handlebars, is abnormal, because it's not what bikes were designed for; having anal sex is abnormal, because it's not what bottoms and penises were evolved for. That's not to say that either activity is wrong (though riding a bike backwards is not a good idea in traffic). I agree that "abnormal" usually has negative connotations, but what other word is there?