Our advice columnist, Prudence, received a letter in May from a woman who barred her partner from sharing a hotel room with a female friend. "I am extremely uncomfortable with the arrangement," she wrote. "Even though she is also in a relationship, and I trust them both, I think this is very inappropriate."

Prudence advised the letter writer to back down: "Even you acknowledge that … the two of them are being upfront about just catching up and are not scheming to get some on the side." But our comments section erupted in dissent. Here's one typical response: "[They're] just asking for trouble. …Things do 'just happen.' " Here's another: "[S]haring a hotel room with an 'old friend' of the opposite sex simply isn't appropriate for people who are in committed relationships with each other." And here's my favorite, which has a sort of propulsive logic: "If the woman is planning on staying with him overnight, they are planning more than conversation. At the very least, they are planning on drinking or using other substances to excess and whatever that leads to."

For skeptics, it doesn't matter that the letter writer claims to trust her boyfriend, or that forbidding the shared use of a hotel room is not a failsafe against infidelity. What matters is the basic arrangement: A man and a woman, alone, with access to a bed. Prudence believes that men and women can meet platonically (even in a hotel). The commenters do not. It's a classic disagreement—one that rehashes the big question about cross-sex friendship in both academic literature and the popular imagination: Are straight men and women able to forget sex and engage with each other in a truly non-romantic fashion?

Hollywood thinks the answer is no. The sociological research is mixed. It suggests, briefly, that some men and women can ignore sex, while others cannot. In a 1997 study of 186 heterosexual college students, for example, 32 percent of females and 57 percent of males reported at least moderate levels of attraction to their closest cross-sex friend. For her 1997 book We're Just Good Friends, on how men and women manage platonic relationships in daily life, Kathy Werking interviewed 50 adult pairs between the ages of 21 and 46. She found that the overwhelming majority had never raised sex as a serious issue.




As for my own research: This past winter I asked Slate readers to fill out a survey on "platonic friendship." I said I was looking for subjects with a "platonic friend," so it's unsurprising that more than half of the 549 respondents who answered all of the relevant questions profess no attraction of any kind—they've never had sex with their friend, never talked about sex, and never thought seriously about it. Just over 5 percent are on the opposite extreme, and report significant sexual tension or ongoing sex. There's a range of experience in the middle—mostly versions of the dating-to-friendship narrative, or accounts of fleeting romantic interest.

The survey indicates that the question "Are straight men and women able to forget sex and engage in a truly non-romantic fashion?" is too narrow. It's wrong to think of platonic friendship as a binary proposition—in which couples either avoid sex entirely and make the relationship work, or they don't and it doesn't. Sexual feeling within friendship exists on a Kinsey-type scale, and moderate attraction does not necessarily ruin or invalidate the relationship. The stories below, picked out from the survey, represent points on a continuum.

(One caveat: I rarely heard from both parties to a friendship, so nearly all of these accounts are one-sided. It's possible that the silent parties have a wildly different perspective on their relationships from what's laid out below. But then again I have no special reason to think that's the case.)




The Platonic Ideal: Brandon & Sue

Brandon and Sue, now in their late twenties, met several years ago in an elevator. It was the first day of graduate school—he was wearing a suit and tie; she was wearing flip-flops. Sue thought Brandon was striving. But by the end of orientation, they had gravitated toward one another, largely because, attire aside, they were superficially compatible: They were two of the only recent-college grads with no professional experience.

Sue and Brandon had an intense workload and found that they studied well side by side. A narrative momentum was pushing them together (they even met cute), but it never led to romance, maybe because Sue was seeing someone else or because they were too busy to think about it. Years later, they have jobs at the same company and live together. They have never slept together.

It's this sort of friendship that most people have in mind when they use the term "platonic friendship." It's also the sort that requires the most robust defense—you need to answer the skeptics who think you're either lying to them or lying to yourself. A colleague of mine suggests that researchers could settle the issue by hooking cross-sex friends up to a plethysmograph machine, then gauging their level of arousal. Short of that, Sue explains the situation by drawing a comparison that, judging from the survey, is a bona fide cross-sex friendship cliché. Brandon, she said, is like family, a "brother type … it would feel incestuous to ever be more than friends." Sue and Brandon are so figuratively familiar that sex is inconceivable. It's on the order of taboo.




Meet Brandon and Sue, Platonic Friends

Falling Into Friendship: Sean & Jody

The first week of college, Jody and Sean met in the laundry room, and, imitating brainy freshmen everywhere, talked for hours about their favorite authors. Sean quickly developed a crush and wrote Jody a passionate note about his feelings. But she was already dating someone else, and she devastated Sean with what he thought was a rather lame offer of friendship.

Jody ran through a couple of boyfriends quickly, while Sean stuck around. At least once, she asked him to break up with a boyfriend on her behalf, but he didn't oblige. By sophomore year, he was over her. Twenty years later, they're married—to other people, and are still friends. Sean was Jody's attendant at her wedding.




When they first met, sex was a factor—for Sean if not for Jody. But at this point, Sean and Jody are like Sue and Brandon in that sex is unthinkable. This is a possibility that Hollywood ignores: Unrequited love gives way, once and for all, to a satisfying platonic bond. It's a common progression, with many respondents describing how, at some early stage, one party or both wanted a physical relationship, but then those feelings dissipated.

Lingering Doubts: Joel & Ruth

Joel and Ruth went to high school together in the mid-90s, but it wasn't until they re-met in a history of philosophy class in college that they became friends. Six or seven months later, when Joel was in a deeply uncommitted relationship with another woman, they started fooling around in the "off stages." Eventually Joel decided he wasn't interested. She slammed the door of his apartment and called him an asshole—a pitch-perfect scene from a romantic comedy. A few days later they were back to being friends.

Today she lives on the East Coast and he lives in the Midwest, where he's finishing his Ph.D. They mainly keep in touch by phone and daily e-mails, and see each other over the holidays.




Joel and Ruth seem further along on this Kinsey-type scale than Sean and Jody—or at least Joel does. He describes Ruth as "simply the perfect woman—she's hot, and I could spend the rest of my life talking to her." He also confesses that, "many times, particularly in the dark, lonely nights of the soul that have comprised my graduate study, I have asked myself if perhaps I was in love with her and had repressed it." Yet he never finds himself wanting to sleep with her, and he doesn't feel the urgency with Ruth that he's felt with other women.

Settling for Friendship: "John" & "Jane"

"Jane" (an anonymous respondent) first encountered "John" in 1989, when she was working in a congressional office and he was working as a reporter on the congressional beat. She'd watched him on television and felt shocked to meet him in person. (She was 23 years old at the time.) He hardly even noticed her. Over the next 17 years she saw him again only once or twice until, four years ago, to Jane's complete amazement, they became friends. Now she's his confidante in personal and financial matters and often works as his personal assistant—though she receives no payment for this position.

Jane, unlike the other respondents, actively wants her friendship with John to become romantic, but she's sure he's not interested, and doesn't want to risk their relationship. Jane's is the classic Hollywood case. She doesn't doubt, as Joel does; rather, like Duckie in Pretty in Pink, her feelings are unrequited and so she settles for friendship.

Repressed Attraction: Kevin & "Lucy"

Kevin, who's in his early fifties, doesn't have "dark, lonely nights of the soul." He knows exactly what he thinks about "Lucy" (not her real name), whom he met in 1989, when he was working as a freelance music journalist. She was a local musician, and they saw each other initially at public events. Then professional admiration gave way to something more personal.

He was, and still is, extremely attracted to her. Kevin also suspects that the attraction is mutual. But they were both married when they met and are still married today, so he's never acted and says he never will. "I do find her desirable and might wish to deepen the relationship if it were ethically possible, which I do not believe it to be. … This is an issue involving morals and honor and fidelity, unfashionable as these concepts are today. The sort of person who would abuse the trust of an old friendship or betray one woman to be with another is not the sort of person I choose to be."

This is a very different sort of beast from the usual understanding of platonic love, but it's not the Hollywood model, either. Because ethical codes and stability are more important to Kevin than acting on his impulses, he feels satisfied with perpetual dissatisfaction.

Modern Love: Eric & Nancy

Nancy and Eric met at a puzzlers' convention in 1992 and had their first conversation, about Lyle Lovett. When Eric invited Nancy into a ménage à trois with his girlfriend, she accepted. Nancy happened to be married, but she figured her husband wouldn't mind, since they were experimenting with "openness."

Eric's girlfriend was a bit of a masochist—hot wax, nipple clamps, paddles, whips. At first, Nancy just watched. Then she participated. But it wasn't her kind of thing, really, in large part because she wasn't actually attracted to either Eric or his girlfriend. Eric and the masochist broke up, but when a new girlfriend came along, Nancy proved her friendship for Eric yet again by looking on. Once she felt so bored she fell asleep.

Sex aside, Nancy and Eric spend time together as other friends do—they talk for hours about their relationships, their careers, their kids, and how strange it is that they've gotten old. (They're in their early fifties.) Eric and Nancy are clearly on the opposite extreme from Sue and Brandon in terms of sex, but neither couple tussles with romantic feeling—they're just friends.

A few months ago a Slate reader e-mailed me to explain that "platonic friendships exist between men, they exist between women, but 99.99 percent of the time a man doesn't have a platonic friendship with a woman, he has an unconsummated sexual relationship with a woman." He added, "However, as a journalist, you've already reached your conclusions."

It's true I had already reached my conclusions, largely because I've experienced a Brandon-Sue type relationship with my closest friend, Jeff. (Or something between a Brandon-Sue and a Sean-Jody.) I'm also not vain enough to think that all the other men I'm friends with secretly wish we were sleeping together. And I don't share my correspondent's mechanical understanding of male sexuality, which posits that men are incapable of seeing a biologically viable sex object as anything but that. If a man does from time to time reflect on a female friend's good looks and feels a stirring of sexual feeling, so what? Does that really mean he can't lay claim to platonic love? Many intense same-sex friendships have an occasional erotic tinge to them, too. In 1903, the Austrian philosopher Otto Weininger wrote that "there is no friendship between men that has not an element of sexuality in it. … Much of the affection, protection, and nepotism between men is due to the presence of unsuspected sexual compatibility"—but he didn't go on to suggest that, therefore, there is no such thing as same-sex friendship. Surely what matters is the persistence or centrality of sexual feeling, rather than transitory attraction.

All that said, having read through hundreds of survey responses, I find the angry reader more deserving of sympathy. There seems to be a linguistic problem with the word friendship—it's used too expansively. Only a cynic with an extremely puritanical understanding of friendship would argue that Sean's feelings as an 18-year-old must forever taint his relationship with Jody. But are Kevin and Lucy really "friends"? For them the phrase unconsummated sexual relationship (as my correspondent put it) may be more accurate.