My high school had the same rule. If you didn’t have a date “of the opposite sex” you couldn’t go. This wasn’t just prom either, homecoming had the same rule. Two girls’ dates backed out on them so they were going to go together. Some school official found out and told them they couldn’t go. They had already bought the tickets, dresses, etc. It’s such crap to force you to have a date. It’s high school… it’s supposed to be fun. Why force people into dates?
As advisor of my school’s gay/straight/bisexual alliance, I can’t help but impishly wonder whether the administration had gotten wind of an epidemic of lesbian pair-ups (at a Catholic school, ‘epidemic’ can mean ‘one couple’), and was trying to force them to arrive at the dance separately.
Love to see the chaperones try to keep the girls from dancing with each other, though…
Our school has that policy too… but anyone who doesn’t have a prom date signs up on this website called Prom Date Depot to find one. There’s usually at least a couple people within an hour’s drive away.