MELBOURNE, AUSTRALIA—Tracing the unique behavior back to the dawn of civilization, researchers at Monash University announced Wednesday that lowering one’s voice to discuss a person’s sexual orientation is a physiological trait that evolved in humans over thousands of years. “The fossil record shows the human larynx completing a transformation around 11,000 years ago, which coincides with the time period when Homo sapiens appear to have begun speculating about their fellow clan members’ sexual preferences in fevered whispers,” said Dr.