yes of course you can tell....but you will have to look at the person for a total of twenty mins. eye to eye contact without either of you blinking.....at the same time you must be fully aroused and ya arousal must be viewed by 5 people of the same gender.....two of which must comment on ya arousal....after which you will be able to notice the genetalia of the intended person...do not be surprised if the person does not have nice genetalia to go along with their nice face....sometimes you can alter the image of the genetalia in ya quest to know.....