While it might have surprised onlookers, undergraduates in the 2000s were in fact having less sex than their predecessors in the 1980s and '90s - if you accepted their definition of sex as vaginal intercourse. (Those of us who grew up during the Clinton years learned from our president that activities other than intercourse do not constitute "sexual relations," however intimate they may be.)
Moira Wegel
clinton, intercourse, sex, statistics