The joke’s on a generation of human-sexuality researchers: Adolescent “pranksters” responding to the widely cited National Longitudinal Study of Adolescent Health in the mid-1990s may have faked “nonheterosexuality.”

Preliminary results from the landmark study – known as “Add Health” – stunned researchers, parents and educators alike, recalls Cornell’s Ritch C. Savin-Williams, professor of human development: “How could it be that 5 to 7 percent of our youth were homosexual or bisexual!” Previous estimates of homosexuality and bisexuality among high schoolers had been around 1 percent.

So imagine the surprise and confusion when subsequent revisits to the same research subjects found more than 70 percent of the self-reported adolescent nonheterosexuals had somehow gone “straight” as older teens and young adults.

“We should have known something was amiss,” says Savin-Williams. “One clue was that most of the kids who first claimed to have artificial limbs (in the physical-health assessment) miraculously regrew arms and legs when researchers came back to interview them.”

Now Savin-Williams is the co-author (along with Kara Joyner of Bowling Green State University) of an invited essay in the journal Archives of Sexual Behavior that was published online Dec. 24, "The Dubious Assessment of Gay, Lesbian and Bisexual Adolescents of Add Health."

The Add Health study (with more than 14,000 participants in four “waves” between 1994 and 2009) was intended to “assess various social and familial contextual variables that influence health, well-being and health-related behaviors” of American young people.

Over the years, analyzing Add Health’s sexual-orientation data became a cottage industry for scholars of human sexuality – Savin-Williams among them. “We offer this essay, with data, to forestall such wrongheaded scholarly work in the future,” Savin-Williams and Joyner wrote.

They offered three hypotheses for the gay-gone-straight phenomenon: Perhaps many of the self-reporting nonheterosexuals went “back in the closet” as they aged. Maybe they misconstrued the researchers’ meaning when asked, rather euphemistically: “Have you ever had a romantic attraction to a male?” and “Have you ever had a romantic attraction to a female?”

Or it could have been a sophomoric joke to claim, in the confidential survey, to be romantically attracted to the same sex. Most of the adolescents who revised their sexual orientation in subsequent surveys were boys – who might have found humor in pretending to be gay or bisexual.

Joyner and Savin-Williams quickly dismissed the first hypothesis, saying that notion is inconsistent with what is known about gay youth development. “Gay high school youth in such numbers do not become closeted during young adulthood,” Savin-Williams noted. “Actually, the developmental progress is the reverse: coming out once away from home.”

They gave more credence to the idea that politically correct language about “romantic attraction” might have been misinterpreted. Questions in subsequent Add Health surveys actually used the “S word,” as in sexual orientation. “We’re guessing,” Savin-Williams says, “that some research subjects ultimately understood the message, that they said: ‘Now I know what you’re asking – and, no, I’m not.’”

That and the adolescent pranksters are the most likely explanations for the “dubious assessment” of Add Health data, the authors conclude.

“I can take a joke as well as the next academic,” says the Cornell professor, a licensed clinical psychologist, author and director of the university’s Sex and Gender Lab who has spent a lifetime studying adolescent development.

Yet he is saddened that the Add Health data led researchers, clinicians and policymakers to an inflated sense that gay youth are more suicidal, depressed and psychologically ill than are straight youth. “We need to be careful,” Savin-Williams said, “when we do our research that our sexual-minority participants are representative of the gay youth population so that we can accurately and adequately represent their lives.”