As the ballroom dancers glided in unison, mirroring each other's pulsating movements to a midtempo Latin beat, a couple in black body-hugging costumes caught the audience's attention. Screaming "Go 201, go 201," the onlookers cheered the pair on as they whirled across the room in an athletically sensuous display of high leg kicks, grinding hip turns and pirouettes. The couple, one of 24 teams dancing in the preliminary round of a ballroom dancing contest at the Massachusetts Institute of Technology, captured second place in the Latin division. Only the couple's sex — both are men — hinted at controversy. In...