In the 1986 movie Stand By Me, an adult protagonist – played by Richard Dreyfuss – looks back wistfully on the friendships he formed in his youth. “I never had any friends later on like the ones I had when I was twelve,” he muses. “Does anyone?”

For most American men, the sad answer is “no.” In surveys, men report that they rarely sustain intimate, long-standing friendships with other males after childhood. And the reason might surprise you: According to a large body of research, they’re afraid of being seen as gay.

I thought of this research as I read about the death of Tyler Clementi, the Rutgers University freshman who jumped off the George Washington Bridge after a roommate secretly filmed Clementi’s sexual encounter with another man and posted the clip online. Clementi died by himself, but he wasn’t alone: Since the school term began in September, three other adolescent boys around the country also committed suicide following taunts from classmates about their sexual orientation.

In response, gay and lesbian groups called on schools to institute more stringent protections for gay students. Even Secretary of Education Arne Duncan got in on the act, attributing these “unnecessary tragedies” to the “trauma” of homophobic bullying. “This is a moment where every one of us . . . needs to stand up and speak out against intolerance in all its forms.”

A longstanding problem – for all

He’s right, of course. But to fight intolerance against gay boys, we also need to acknowledge its toll on straights – and our entire culture. Homophobia hurts all of our boys, by driving a wedge between them. Sharing your deepest feelings with another man? That’s so . . . gay. Or so we’ve been taught.

And we’ve known about this problem for a long time. In the early 1980s, observing hundreds of elementary-school boys, sociologists Barrie Thorne and Zella Luria noticed that kindergarteners and first-graders hugged, joined arms, and held hands. But by fifth grade, boys had forsaken these customs in favor of mock violence – poking, pushing, and shoving – or ritual gestures like high-fives.

Why? As they got closer to puberty, the boys began to use homophobic epithets – homo, queer, and especially fag – to demean each other. So they couldn’t risk bringing those labels onto themselves. “As ‘fag’ talk increases, relaxed and cuddling patterns of touch decrease,” Thorne and Luria wrote. “The tough surface of boys’ friendships is no longer like the gentle touching of girls.”

And it’s not just physical intimacy that decreases, of course. Other scholars watched teenaged boys at the movies, where they often sat apart even if they came in together. Most of all, they avoided showing their emotions to each other. Even at a tear-jerk movie, it seems, boys aren’t supposed to cry. That’s “gay,” too.

Male affection used to be ok

It wasn’t always that way. In the nineteenth century, American men declared their love for each other in fiction, poetry, and song. And you can see it in photographs from the period, as well, which show men posing in physical embrace – sharing a chair, holding hands.

All of that began to change in the early 20th century, when new fears of “feminization” started to drive men apart. As America urbanized, the argument went, men were losing the rough-hewn virtues of the old frontier. So educators began to emphasize competitive sports, especially football, which would restore the nation’s endangered masculinity. And they also warned about “sissies” or “fairies,” which in turn led men to turn away from each other.

During World War II, as the historian John Ibson has shown, American military men would enjoy a brief revival of the old intimacies. Thrown together on ships or in foreign countries, they celebrated male camaraderie in ways that might shock us today. Consider “My Buddy,” a popular song of the era, in which one soldier mourns the absence of the other:

Nights are long since you went away

I think about you all through the day

Miss your voice, the touch of your hand

I long to know that you’ll understand

My buddy, my buddy

Your buddy misses you

A new homophobia

But these patterns would disappear in the 1950s, when a new homophobia stalked the land. In Congress, Joseph McCarthy and other red-baiters argued that gay men were often Communists as well. Psychologists warned against overprotective mothers, whose worries and anxieties would supposedly render their sons into homosexuals.

The boys heard the message, of course, distancing themselves from each other. And you can hear the message still, at any school or playground, where they call each other homo, fag, or queer. That hurts the gay kids most of all, as the awful death of Tyler Clementi reminds us. But it hurts the rest of us, too, by limiting the ways that men can act and feel. And that’s bad news for all American men, and for anyone – male or female – who loves them.

Jonathan Zimmerman teaches history and education at New York University. He is the author of “Small Wonder: The Little Red Schoolhouse in History and Memory.”