Population-based studies, Dr. Diamond said, indicate that bisexuality is in fact more common than exclusively same-sex attraction, and that female libido is particularly open-ended. That may explain why female bisexuality is more conspicuous in popular culture, from Katy Perry’s “I Kissed a Girl” to “The Kids Are All Right” and the Netflix series “Orange Is the New Black.” (That straight men may find it titillating doesn’t hurt.)
In a recent Modern Love essay in The New York Times revealing her relationship with another woman, the actress Maria Bello wrote, “My feelings about attachment and partnership have always been that they are fluid and evolving.” Before marrying Bill de Blasio, Chirlane McCray identified as a lesbian, which has become part of the progressive credentials of New York’s first family.
Male bisexuality, by contrast, is more vexed, and much of the skepticism comes from gay men. In the aftermath of Mr. Daley’s announcement, Ann Friedman wrote a post for New York Magazine’s The Cut blog predicting that male bisexuality would become more visible as gender mores evolved. “Traditional definitions of masculinity — which tend to go hand in hand with homophobia — are going through a real shake-up,” Ms. Friedman wrote. “More hetero men are tentatively admitting that they’re turned on by certain sex acts associated with gay men.”