The topic was more discussed for special groups, such as homeless and unstably housed women, or black cisgender sexual minority men, and less specifically for MSM student groups^21,22,23. Many studies have shown that sexual orientation is one of the factors influencing high-risk sexual behaviors of HIV infection, but less complex relationship models such as mediation effect have been considered. In this study, we explored the overlap of the three variables(sexual orientation, gender identity, intention to marry or date a woman) and internal relationship between them. We also examined associations between the three variables and HIV prevention outcomes, based on the mediation model.

Relationships between sexual orientation, gender identity, and intention to marry or date a woman

We found that for gay participants, roughly one quarter of gay men reported an intention to marry or date a woman, while almost half of bisexual/other sexual orientation men reported no intention to marry or date a woman. Redd Driver’s study revealed that only a small proportion of black sexual minority men reported overlap in their sexual identity, sexual attraction, and sexual behavior, which was lower than results of this study²³. In this study, for those identified as male, almost half of them reported as gay and no intention to marry or data a woman. The divergence across aspects of sexual orientation among MSM may reflect the influence of oppressive intersecting macro-level stigmas (e.g., racism, homophobia, and biphobia)^24,25. In China, people have a relatively limited understanding of sexual orientation, which could be affected by attitudes encouraged by traditional culture, such as a low tolerance for bisexual or gay people, and the feeling that a son should have a baby to carry on his family name²⁶. This study provides quantitative results, but further research is needed to explore the factors causing disparity.

Using chi-square testing, we found a preliminary association between sexual orientation and an intention to marry or date a woman among college students MSM, while no relationship was found between gender identity and the other two variables. Research in China showed that those self-identified as bisexual reported a greater intention to marry or date a woman²⁷. With social changes, however, the pressure from society and family is gradually decreasing, which is why half of the bisexual students in this study did not plan to marry or date a woman. Student identity might be another important reason why they had no intention of marrying or dating a woman.

We hypothesized that gender identity would be associated with sexual orientation and attitude toward marriage. The association between gender identity and sexual orientation among sexual minority groups have been widely discussed and have been shown to be related to each other in many countries such as Europe^28,29, but this association was not found in this study, Compared to sexual orientation, people pay less attention to gender identity in China. In this social context, an individual’s understanding of their own gender is relatively limited and has not yet had an impact on sexual orientation or attitude regarding marrying or dating women.

Effects of sexual orientation, gender identity, and intention to marry or date a woman on HIV prevention outcomes

Our study provided a clear picture of the impact of sexual orientation, gender identity, and the intention to marry or date a woman on HIV prevention outcomes. Our results suggest that sexual orientation has a direct effect on HIV knowledge and HIV self-testing. Those reporting bisexual/uncertain sexual orientation tend to undergo less self-testing and have less HIV knowledge, in contrast to a study of SMM²³, but consistent with other studies^23,30. In Zhejiang Province, the majority of HIV information transmission and HIV self-testing services are supported by CBOs and less by voluntary counselling and testing clinics. Compared with gay men, bisexual men and bisexuals have fewer opportunities and less frequent contact with CBOs, especially college students. Furthermore, bisexual students tended to be more afraid of having others discover their sexual orientation³¹. Those who had disclosed their sexual orientation to some or all of the members of their network were more aware of PrEP than their counterparts, who reported lower levels of disclosure³². The unique health and intervention needs of these subjects should be studied, especially for those who face barriers when accessing services.

We also found a mediating effect of sexual orientation on HIV knowledge through intention to marry or date a woman in another direction. Intending to marry a woman implies taking on more responsibility to protect their spouse and baby, and that more attention is paid to the acquisition of HIV knowledge²⁷. However, there was no mediating effect of sexual orientation on HIV self-testing through intention to marry or date a woman. The most likely reason for this finding might be that many factors affect the use HIV self-testing, such as the accessibility of the service or stigma^33,34.

It should be noted that since the Cronbach’s α coefficient of the HIV knowledge scale is only 0.482, its internal consistency is not particularly high. This may indicate that the results only reflect part of the knowledge level rather than the overall knowledge level. In this study, Only 40% of respondents answered Question 3 correctly, while over 90% answered Question 2 correctly.

PEP and PrEP are effective at preventing HIV infection. However, no study has examined the effects of sexual orientation on the acceptance or use of PrEP/PEP among college students MSM. However, many studies have revealed a relationship between sexual orientation and PrEP among MSM in general^35,36. Research on American MSM showed that bisexual participants were 2.1 times less likely to be prescribed PrEP than gay men³⁵.

Our multivariate logistic regression analyses showed a mediating effect of sexual orientation on having taken PEP and having heard of PrEP via intention to marry or date a woman, while no direct effect of sexual orientation on the outcomes was observed. intention to marry or date a woman was the key factor. Interestingly, the effect of intention to marry or date a woman had opposite effects on having heard of PrEP and having taken PEP. College students MSM who reported an intention to marry or date a woman were more likely to report having taken PEP and having never heard about PrEP. We believe that this is related to service accessibility and urgency³⁷. In Zhejiang, approximately 90 hospitals are designated PEP hospitals, with at least one in each county. These institutions have unified management requirements for medication and follow-up. By contrast, PrEP does not have such standardized management. Furthermore, less contact with CBOs and insufficient key information on HIV in schools may explain their insufficient information on PrEP³⁸.

Our findings suggest that a comprehensive examination of sexual orientation among college students MSM is urgently required, not just by means of one or two measures in observational and interventional HIV-related research. Public health researchers have failed to address the health risks associated with sexual orientation adequately, and the need for corresponding differentiated intervention policies among college students MSM. To improve the effectiveness of intervention, identifying unique subgroups and developing tailored programs that address multi-level factors may help improve the situation among college students MSM.

The study findings should be viewed in the context of the study’s limitations. Firstly, it was a cross-sectional study, which weakens the ability to make causal inferences. Secondly, the CBOs used convenience sampling, which is not representative of all college students MSM. We increased the variety of sample sources (online and offline) to offset this deficiency. Thirdly, self-reported data may lead to information bias. Face-to-face training before investigation may reduce the bias. Fourthly, the internal consistency of the HIV knowledge assessment scale is relatively low, and a more scientifically designed knowledge scale needs to be developed. Fifthly, there is a possibility of residual confounding given that we only controlled for four individual-level factors in the multivariate models. Future longitudinal studies should control for more confounders, including network-level and structural factors, when examining associations between sexual orientation and HIV prevention outcomes.