One of the most radical shifts in interpersonal relationship patterns over the past few decades has been the increase in platonic (nonsexual) friendships between men and women in the United States and Canada. In the nineteenth century, friendships were almost exclusively same-sex, and throughout most of the twentieth century, cross-sex friendships remained a rarity (Halatsis & Christakis, 2009). As we move into the twenty-first century, however, this is changing.

Most cross-sex friendships are not motivated by sexual attraction (Messman, Canary, & Hause, 1994). Instead, men and women agree that through cross-sex friendships, they gain a greater understanding of how members of the other sex think, feel, and behave (Halatsis & Christakis, 2009). For men, forming friendships with women provides the possibility of greater intimacy and emotional depth than is typically available in male-male friendships (Monsour, 1997).

Despite changing attitudes toward cross-sex friendships, men and women face several challenges in building such relationships. For one thing, society tends to segregate the sexes from early childhood. In most schools, young boys and girls are put in separate gym classes, line up separately for class, and engage in competitions pitting “the boys against the girls” (Thorne, 1986). It’s no surprise, then, that young children overwhelmingly prefer friends of the same sex (Reeder, 2003). As a consequence, most children enter their teens with only limited experience in building cross-sex friendships. Neither adolescence nor adulthood provides many opportunities for gaining this experience. Leisure-oriented activities such as competitive sports, community programs, and social organizations—including the Boy Scouts and Girl Scouts—typically are sex segregated (Swain, 1992).

Another challenge is that our society promotes only same-sex friendship and cross-sex coupling as the two most acceptable relationship options. So no matter how rigorously a pair of cross-sex friends insist that they’re “just friends,” their surrounding friends and family members will likely meet these claims with skepticism or even disapproval (Monsour, 1997). Family members who approve of the friendship often pester such couples to become romantically involved: “You and Jen have so much in common! Why not take things to the next level?” If families disapprove, they encourage termination of the relationship: “I don’t want people thinking my daughter is hanging out casually with some guy. Why don’t you hang out with other girls instead?” Romantic partners of people involved in cross-sex friendships often vehemently disapprove of such involvements (Hansen, 1985). Owing to constant disapproval from others and the pressure to justify the relationship, cross-sex friendships are far less stable than same-sex friendships (Berscheid & Regan, 2005).