If we’re looking for an explanation of why today’s teens are having less sex than previous generations, there’s this: Many of them spend months or even years dating without ever meeting face to face.

When Nicole Nguyen was 16, she met her first serious boyfriend for the first and last time—after they’d broken up. They had 20 minutes. They hugged once. It only happened because that day, they just happened to find themselves in the same state.