Here's a recipe for homophobia, psychologists say: Mix repressed same-sex attraction with authoritarian parents. Simmer for 18 or more years.

College students who said they felt more controlled or pressured by their parents tended to have a greater discrepancy between their reported sexual orientation and their actual orientation as determined by a psychological test, researchers from the University of Essex, the University of California, Santa Barbara, and the University of Rochester (N.Y.) found.

And students who had the greatest sexual identity conflict -- young men and women who reported a straight identity while scoring highest on homosexual tendencies -- also exhibited a number of behaviors consistent with homophobia. They tended to report more negative or fearful attitudes toward gays and lesbians, tended to be biased against homosexuals in hypothetical situations, and were more likely to endorse anti-gay policies.

In many cases these are people who are at war with themselves and they are turning this internal conflict outward, co-author Richard Ryan, a professor of psychology at the University of Rochester, said in a statement.

The scientists described their results in a paper published last week in the Journal of Personality and Social Psychology.

The conjectured link between homophobia and unwanted homosexual tendencies has its roots in Sigmund Freud's description of reaction formation, a defense mechanism wherein a person overcompensates for emotions and impulses that cause them anxiety by aggressively pursuing the opposing tendency.

Other researchers have unearthed physical evidence to support this theoretical framework. In 1996, the Journal of Abnormal Psychology published a study from three University of Georgia researchers who studied homosexual arousal in self-identified heterosexual men.

In this experiment, the researchers hooked the subjects' penises up to devices that measured the degree of their erections, and showed them pornography. All the men responded to videos of heterosexual and lesbian intercourse, but only the men that showed signs of homophobia based on a questionnaire developed erections in response to homosexual male coupling.

Homophobia is apparently associated with homosexual arousal that the homophobic individual is either unaware of or denies, the Georgia researchers wrote in 1996.

One of the challenges to studying repressed homosexuality is, obviously, how to identify same-sex attraction in someone who says they are straight. No technique is fool-proof.

In the current study, researchers used a technique to identify subjects' implicit sexual orientation that involved sorting words and pictures into gay and straight categories.

But before the subject began the task, he or she was primed with a subliminal message: The word me or others was flashed across the screen for a fraction of a second, long enough to be unconsciously perceived but too quick to be consciously noted.

The researchers then measured how long it took the students to sort the pictures into the categories. If a subject was quicker to identify words and pictures associated with homosexuality than heterosexual ones after being primed with me, their implicit orientation leaned gay.

There are other limitations to these studies, the authors acknowledge; all of the subjects in the four studies conducted no longer live at home with their parents.

It may be helpful to test these effects in younger adolescents still living in the home and in older adults who have spent a longer time away from parents' influence, the authors wrote.