If men are from Mars and women are from Venus, it may explain at least one of their shared beliefs: Men and women can't be real friends. Blame the sexual tension that almost inevitably exists between any red-blooded, heterosexual man and woman. There's a point of jealousy that plagues many rational people when a significant other befriends someone of the opposite sex. Boil it down to the inherent differences between the sexes. It just can't be done. Right?

Wrong, say relationship experts. "The belief that men and women can't be friends comes from another era in which women were at home and men were in the workplace and the only way they could get together was for romance." explains Linda Sapadin [PhD], a psychologist doing private practice in Valley Stream, New York. 'Now they work together, have sports interests and socialize together.' This cultural shift is encouraging psychologists, sociologists and communications experts to put forth a new message: Though it may be tricky, men and women can successfully become close friends. What's more, there are good reasons for them to do so.

Society has long singled out romance as the prototypical male-female relationship because it spawns babies and keeps the life cycle going. Cross-sex friendship, as researchers call it, has been either ignored or trivialized. We have rules for how to act in romantic relationships (flirt, date, get married, have kids) and even same-sex friendships (boys relate by doing activities together, girls by talking and sharing). But there are so few platonic male-female friendships on display in our culture that we're at a loss to even defining these relationships.

But that's only one of the major barriers. In 1989, Don O'Meara, [PhD], a sociology professor at the University of Cincinnati-Raymond Walters College, published a landmark study in the journal 'Sex Roles' on the top impediments to cross-sex friendship. "I started my research because one of my best friends is a woman," says O'Meara. "He said, 'Do you think anyone else has the incredible friendship we do?' He decided to find out and after reviewing the scant existing research dating back to only 1974, O'Meara identified the following four challenges to male-female friendship: defining it, dealing with sexual attraction, seeing each other as equals and facing people's responses to the relationship. A few years later, he added a fifth: meeting in the first place.

CHALLENGE #1
Defining the Relationship: Friends or lovers?
Platonic love does exist, O'Meara asserts, a study of 20 pairs of friends published in the Journal of Social and Personal Relationships lends credence to the notion. In it, Heidi Reeder, [PhD], assistant professor at Boise State University confirms that "friendship attraction" or a connection devoid of lust is a bona fide type of bond that people experience. Distinguishing between romantic, sexual and friendly feelings, however, can be exceedingly difficult.

CHALLENGE #2
Overcoming Attraction: Let's talk about sex
The reality that sexual attraction could suddenly enter the equation of a cross-sex friendship uninvited is always lurking in the background. A simple, platonic hug could instantaneously take on a more amorous meaning. "You're trying to do a friend-friend thing," says O'Meara, "but the male-female parts of you get in the way. Unwelcome or not, the attraction is difficult to ignore."

CHALLENGE #3
Establishing Equality: The power play
Friendship should be a pairing of equals. But, O'Meara says, "In a culture where men have always been more equal than women, male dominance, prestige and power is baggage that both men and women are likely to bring to a relationship." Women are at risk of subconsciously adopting a more submissive role in cross-sex friendships, he says, although that is slowly changing as society begins to treat both genders more equally.

CHALLENGE #4
The Public Eye: Dealing with doubters
Society may not be entirely ready for friendships between men and women that have no sexual subtext. People with close friends of the opposite sex are often barraged with nudging, winking and skepticism: "Are you really just friends?" This is especially true, says O'Meara, of older adults, who grew up when men and women were off-limits to each other until marriage.

CHALLENGE #5
The Meeting Place: Finding friends
As the workplace and other social arenas become increasingly open to women, the sexes are mingling more and more. Still, men and women continue to have surprisingly few opportunities to interact.

These obstacles may seem numerous and formidable, but male-female friendship is becoming not only a possibility but also a necessity. If men and women are to work, play and coexist in modern society, researchers believe men and women must learn to understand and communicate with each other.

To that end, social scientists like Sapadin, Monsour and O'Meara have begun studying how to do just that. The field of research is still in its infancy, but they are now beginning to understand some basic truths about male-female friendship:

TRUTH #1 : Friendship is not equal opportunity, Not until high school does puberty really draw boys and girls together, which then continues into college. But as people develop serious romantic relationships or get married, making and maintaining cross-sex friendships becomes harder.

The number of cross-sex friendships continues to decline with age--not surprising, because most adults grew up in an age where consorting with the opposite sex outside of wedlock was taboo. According to Rosemary Blieszner [PhD], a family studies professor at Virginia Tech and author of Adult Friendship (Sage, 1993), elderly people rarely form new friendships with members of the opposite sex. Her research shows that only about 2 percent of the friendships elderly women have are with men.

TRUTH #2 : Men benefit more from cross-sex friendship than women, There are proven and apparent distinct differences between female friendship and male friendship. Women spend the majority of their time together discussing their thoughts and feelings, while men tend to be far more group-oriented. Males gather to play sports, travel or talk stock quotes; rarely do they share feelings or personal reflections. This may explain why they seem to get far more out of cross-sex friendship than their female counterparts.

TRUTH #3 : But women benefit, too, All that sharing and discussing in female-female friendship can become exhausting, as any woman who's stayed up all night comforting a brokenhearted girlfriend can attest. With men, women can joke and banter without any emotional baggage. "Friendships with men are lighter, more fun," says Sapadin. "Men aren't so sensitive about things. They also liked the protective, familial and casual warmth they got from men, viewing them as surrogate big brothers. What they liked most of all, however, was getting some insight into what guys really think.

TRUTH #4 : Cross-sex friendships are emotionally rewarding, Although women dig men's lighthearted attitude, most male-female friendships resemble women's emotionally involving friendships more than they do men's activity-oriented relationships, according to Kathy Werking, [PhD],an assistant professor of Communications at Eastern Kentucky University and author of We're Just Good Friends (Guilford, 1997). Her work has shown that the No.1 thing male and female friends do together is talk one-on-one. Other activities they prefer like dining out and going for drives simply facilitate that communication. In fact, Werking found, close male-female friends are emotionally very supportive if they continuously examine their feelings, opinions and ideas.

TRUTH #5 : It's not all about sex, "In reality, sex isn't always on the agenda," says Werking. "That could be due to sexual orientation, lack of physical attraction or involvement in another romantic relationship." After all, even friends who are attracted to each other may also recognize that qualities they tolerate in a friendship wouldn't necessarily work in a serious romantic relationship. And after years of considering someone as a friend, it often becomes difficult to see a cross-sex pal as a romantic possibility.

Of pairs that do face the question of lust, those that decide early on to bypass an uncertain romantic relationship are more likely to have an enduring friendship, says Werking. One study published in the Journal of Social and Personal Relationships by Walid Afifi, [PhD], of Penn State University showed that, of more than 300 college students surveyed, 67 percent reported having had sex with a friend. Interestingly, 56 percent of those subjects did not transition the friendship into a romantic relationship, suggesting that they preferred friendship over sex.

TRUTH #6 : Male-female friendships are political, Men and women have increasingly similar rights, opportunities and interests, which can make cross-sex friendship very political, notes Werking. "It upsets the agreed-upon social order," she explains. "Women and men engage in an equal relationship or they aren't friends. For one thing, new generations of kids grow up believing that boys can play with dolls and girls can take kickboxing, and they're crossing paths more frequently as a result.

Men and women are also becoming more androgynous as their societal roles become more similar. "Men are more willing to have feminine characteristics and women are a lot more willing to admit to traditionally masculine characteristics, like assertiveness," says Monsour. His dissertation showed that women and men categorized as androgynous had twice the number of cross-sex friends.

Whatever the challenges of male-female friendship, researchers agree that to succeed as friends, both genders have to openly and honestly negotiate exactly what their relationship will mean whether sexual attraction is a factor and how they'll deal with it and establish boundaries. In Afifi's and Reeder's studies, the friendships that survived and even thrived after sex or attraction came into play, were those in which the friends extensively discussed the meaning of the sexual activity and felt confident and positive about each other's feelings. Once they got past that, they were home free.