Why are young people having less sex than the previous generation? "'That's the $100,000 question,' said Bill Albert, chief program officer for the National Campaign to Prevent Teen and Unplanned Pregnancy. Some experts say an emphasis on abstinence may have played a role. Some say concern about sexually spread diseases may have been a factor—perhaps instilled by parents who watched the AIDS crisis unfold. Still others suggest this is a generation less inclined to experiment with drugs and sex than its predecessors. The study, released Thursday, is based on interviews with about 5,300 young people, ages 15 to 24."