At home, most of us share a bathroom with a sibling of the opposite sex or with a spouse. Granted, these examples don't involve men and women using the same bathroom at the same time, but I don't see what the big deal is. This is the end of the 20th century, and we're somehow still afraid of sharing bathrooms. I doubt that. Everywhere I look, I see half-naked or scantily clad men and women on billboards, magazine covers, in movies and on television.
Sex is used to sell everything.
Every cover of Cosmopolitan advertises a new sexual position or technique to be found within its pages. At some point, most all of us will be married and sharing a bathroom with a husband or wife every day. Co-ed bathrooms at home are the norm. When I lived in the dorms, the bathrooms in each wing were designated for men or women. However, it never failed that at least twice a week, I would run into a guy in the women's bathroom, usually late at night.