STATISTICS, especially on a subject as intimate as sexuality, have a way of reducing humanity to faceless abstractions. In gathering material for this week's cover story on the sexual activities and attitudes of American teenagers, we concentrated on people rather than printouts. Our correspondents interviewed parents, school counselors and behaviorists, but the most fascinating stuff came, of course, from the scores of youngsters with whom our reporters talked.

"Teenagers still giggle, still take their social lives very, very seriously," says Correspondent Christopher Cory, who interviewed students at Tenafly (N.J.) Senior High School.

"But for many of them, intercourse has become an openly admitted part of dating."

Cory, 31, the father of two young children, interviewed a cross section of 15-to 19-year-olds recruited with the help of school administrators and teachers. The discussions were conducted in a counselor's living room, in the students' homes and at a local coffee shop. Periodically nonplused by the students' candor, Cory was also occasionally ill at ease for quite different reasons. "I could see the eyebrows of the coffeehouse hostess rise," he says, "when I showed up for the second day to buy lunch for a different teen age girl."

Stringer Lou Dolinar, 22 and unmarried, spent a week at the University of Pittsburgh talking to on-and off-campus residents. A June graduate of Columbia University, he was closer in age to his subjects than Cory, but that caused its own brand of problems. Girls were continually on guard for ulterior motives, and after one particularly disappointing interview, Dolinar realized that he was suspected of being a narcotics agent. When he established his identity beyond doubt, the student sat down for more revealing conversation.

The reports by Cory, Dolinar and many others went to Contributing Editor Virginia Adams, who has written five previous cover stories in the Behavior section. Senior Editor Ruth Brine, who edited this week's article, brought a personal perspective to the assignment; one of her sons is a teen-ager and another son and daughter recently were. "Both teenagers and their parents suffer their share of uncertainties in this new atmosphere," says Brine. "We can't presume to tell any of them what they should or shouldn't do. Rather we tried to report on what people are doing, why, and what some of the consequences are."

This file is automatically generated by a robot program, so reader's discretion is required.