“…"Mostly heterosexuality" has grown in visibility in recent years: In 2014 it was added as an identity category by the popular dating website OkCupid, and a growing number of young celebrities openly claim "mostly heterosexual," "fluid," or "heteroflexible" identities (Renfro & Ahlgrim, 2020). A diverse range of experiences are subsumed under this umbrella: Some individuals report feeling they are "straight-leaning" bisexuals; others report having fallen in love with only one same-gender partner; others pursue sporadic sexual gratification from same-gender partners when other-gender partners are unavailable (Diamond, 2008;Feinstein et al, 2020;Garvey et al, 2018;Kort, 2014;Redcay et al, 2018;Savin-Williams & Vrangalova, 2013;Thompson & Morgan, 2008;Vrangalova & Savin-Williams, 2012, 2014Zane, 2016). Such diversity makes it difficult to interpret the "mostly heterosexual" subgroup: Are they heterosexuallyleaning bisexuals, "fluid" heterosexuals, or a mixture of both?…”