ethnographic references to cross-sex friendships across cultures. Therefore, for much of ancient human history, cross-sex friendships were not common. Today, men and women interact in non-romantic, supportive ways in all types of contexts: work, sports, education, and hobbies, yet these unions are not based on sexual intentions. Evolved mating strategies were mentioned earlier and can be dovetailed with this biological history. Controversies Participants in cross-sex friendships face many challenges, including learning how to navigate the particular type of friendship. The four types of cross-sex friendship as defined by Guerrero and Chavez (2005) referenced earlier are: strictly platonic, mutual romance, desires romance, and rejects romance. In addition, O’Meara (1989) originally stated that the four essential challenges cross-sex friends face are: 1) determining the type of emotional bond experienced in the relationship, 2) confronting the issue of sexuality, 3) dealing with the issue of relationship equality within a cultural context of gender inequality, and 4) the challenge of public relationships — presenting the relationship as authentic to relevant audiences. Schnoonover (2014) built research upon O’Meara's audience challenge and found that members of Guerrero and Chavez's (2005) different friendship types may experience challenges differently. For example, for “mutual romance” couples, members may be approaching the preliminary romantic stage of the relationship and if their romantic feelings feed into their behaviors toward each other, then they will be the most likely to be mistaken for a romantic couple. In contrast, “strictly platonic” friends should be the least likely to prompt the audience challenge. “Desires romance” and “rejects romance” couples may also be subject to the audience challenge — if observers of the friendship see the member acting in a romantic manner or admitting romantic intent, the observers might be more likely to regard the cross-sex friendship as a growing romantic relationship more so than a friendship. Another controversial question surrounding cross-sex friendships that is often raised is - after two romantic partners end their relationship — or more colloquially, “break up” — can they still be platonic friends? Kenny and Schneider (2000) found three major conclusions about cross-sex friendship with a romantic history. First, rebranding a discontinued romantic relationship as a friendship is common in modern American culture. Second, there are particular predictors of whether a friendship will occur after romance. One critical factor is whether there was a platonic friendship before the romantic relationship existed. Because the partners knew how to navigate friendship