If he wasn't Abnegation, I'm sure the girls at school would stare at him.
Does he go to an Abnegation-only school? Because if kids of mixed factions are allowed to go to school together, they'll stare no matter what he is. AND ACTUALLY, GIRLS WILL STARE FURTIVELY EVEN IF THEY ARE ABNEGATION, RIGHT? Nothing you do will stop girls from staring at good-looking guys. Nothing, okay?