In high school, most of the guys in gym class would go shirtless. When it came to electing which sport I wanted to participate in, I selected the girl ones. I had got in trouble playing tennis. It was hot and muggy, so I had taken off my shirt. Never mind that I was male, and shaped like a stick figure, I had to put my shirt back on.
Apparently, someone saw me from the back, and thought I was one of the girls, and made a complaint.
These days, if I wear a sun dress, guys get aroused.