I remember hearing Paul Harvey on the radio, back in the 1970s, explaining a “foolproof” method for telling long-haired boys from girls (obviously assuming college students or younger): How do they carry their books? Boys carry their books in one hand, at their side. Girls clutch their books to their chests.
Not sure if that would work nowadays, since both boys and girls seem to have to wear massive backpacks to carry everything.
Yep, that was in the National Lampoon “Are You a Homo?” test too. If you clutched your books across your chest, also it was easier to see the time if the watch face was on the inner wrist. And if you wore preppy sweater vests with diamond patterns…