LAUSR

The sexual partnerships of transmasculine (TM) adults—those assigned female at birth who identify as transgender men or a masculine spectrum gender identity—and characteristics associated with STI/HIV risk behavior remains understudied. Participants in the current study were TM adults (n = 141) receiving care at a community health center in Boston, Massachusetts between March 2015 and September 2016. Using generalized estimating equations, we examined individual- and partnership-level factors associated with TM adults’ odds of engaging in sexual behavior with a sexual partner of unknown STI/HIV status in the past 12 months. TM adults with casual sexual partnerships (vs. monogamous partnerships) and those in partnerships with cisgender men, other TM individuals, or transfeminine partners (vs. cisgender women) had statistically significantly higher odds of engaging in sexual behavior with a partner of unknown STI/HIV status in the past 12 months. Findings may inform future efforts to improve sexual health communication and STI/HIV disclosure between TM adults and their sexual partners.