Utilizing network analysis to understand the structure of depression in Chinese adolescents: Replication with three depression scales.

Depression involves a heterogenous collection of symptoms. Network perspective views depressive symptoms as an interrelated network. The current study aimed to replicate network analyses on adolescent depression in three samples assessed with three instruments to examine the consistency of network structures and also examine the variance of networks between genders. Three samples of adolescents (total N = 4375, mean age = 15, 49.1% boys) were assessed with PHQ-9, SMFQ and CDI, respectively. Network analyses were carried out on depression symptoms. Network stability, node centrality and network comparisons between genders were examined. Three networks were reliably stable. Sadness and self-hatred were unanimously identified to be central symptoms of adolescent depression in three networks. In addition, fatigue, no good, everything wrong and loneliness also appeared to be central in specific networks. Among three depression networks, PHQ-9 network demonstrated gender difference in network structure. The current study is exploratory in nature. The differences in three networks can be due to various samples or different node inclusions. Further, the study is cross-sectional precluding causal interpretation and the samples are nonclinical. Besides "hallmark" symptom sadness, self-hatred was also identified unanimously in three networks, which demonstrated the significant role self-worth played in adolescent depression. The results also suggested that differences in node inclusion may have influence on the network structure. Supplementary Information: The online version contains supplementary material available at 10.1007/s12144-022-03201-z.

Perceptions of power and sexual pleasure associated with sexual behaviour profiles among Latino sexual minority men.

In a body of research typically focused on risk reduction and disease prevention, other factors motivating the sexual behaviours of Latino sexual minority men, such as resource-based power and sexual pleasure, are less well understood. To this end, Latino immigrant sexual minority men living in New York City were surveyed about their sexual behaviours, perceived power differentials, and pleasure from insertive and receptive anal intercourse. Power and pleasure were examined as associations with behavioural profiles identified through latent class analysis, adjusting for age and partner type. Four latent classes of Latino sexual minority men were identified based on behaviours reported during the most recent sexual event: behaviourally insertive (14.2%), behaviourally versatile (25.9%), behaviourally receptive (29.2%), and limited penetrative behaviour (30.7%). Participants who derived pleasure from insertive and receptive anal intercourse had higher odds of belonging in the behaviourally insertive and behaviourally receptive class, respectively. Perceptions of resource-based power were not associated with class membership. Findings highlight the importance of sexual pleasure as a driver of sexual behaviour, irrespective of power dynamics. Sexual health curricula and interventions for sexual minority men should consider sexual pleasure and sex-affirmative frameworks when providing sexuality education and promoting sexual wellbeing.

Latino Sexual Beliefs Scale: An Exploratory Factor Analysis of Latino Men Who Have Sex With Men.

The catalyzing forces behind risky sexual behavior are a rich area of interest for public health researchers concerned with reducing HIV risk. Social cognitive theory would suggest that sexual beliefs are a viable example of one such influential agent. Recognizing that culture plays an important role in forming such sexual beliefs, and seeking to understand the unique HIV risks present for Latino men who have sex with men (MSM), this article presents an exploratory factor analysis of the 13-item Latino Sexual Beliefs Scale (LSBS) created as part of a larger study to investigate predictors of condom use among a sample of 482 MSM born in Brazil, Colombia, and the Dominican Republic and living in the U.S. The current analysis identified two psychometric factors in the LSBS as Romantic Exigency (containing six items with a mean loading of .62) and Sexual Acquiescence (containing seven items with a mean loading of .57). This is the first factor analysis conducted on the 13-item LSBS and represents the first known quantitative measure of Latino cultural sexual beliefs related to condom use for Latino MSM. Implications for future research include further validation, use in studies exploring the role of sexual beliefs on condom use, and possible thematic targets in HIV risk reduction interventions.

HIV Prevalence and Awareness of Positive Serostatus Among Men Who Have Sex With Men and Transgender Women in Bogotá, Colombia.

OBJECTIVES: We estimated HIV prevalence among men who have sex with men (MSM) and transgender women in Bogotá, Colombia, and explored differences between HIV-positive individuals who are aware and unaware of their serostatus. METHODS: In this cross-sectional 2011 study, we used respondent-driven sampling (RDS) to recruit 1000 MSM and transgender women, who completed a computerized questionnaire and received an HIV test. RESULTS: The RDS-adjusted prevalence was 12.1% (95% confidence interval [CI] = 8.7, 15.8), comparable to a previous RDS-derived estimate. Among HIV-positive participants, 39.7% (95% CI = 25.0, 54.8) were aware of their serostatus and 60.3% (95% CI = 45.2, 75.5) were unaware before this study. HIV-positive-unaware individuals were more likely to report inadequate insurance coverage, exchange sex (i.e., sexual intercourse in exchange for money, goods, or services), and substance use than other participants. HIV-positive-aware participants were least likely to have had condomless anal intercourse in the previous 3 months. Regardless of awareness, HIV-positive participants reported more violence and forced relocation experiences than HIV-negative participants. CONCLUSIONS: There is an urgent need to increase HIV detection among MSM and transgender women in Bogotá. HIV-positive-unaware group characteristics suggest an important role for structural, social, and individual interventions.

Sex work among men who have sex with men and transgender women in Bogotá.

This qualitative study examined sex work among internally displaced male and transgender female sex workers in Bogotá, Colombia. Internal displacement has occurred in Colombia as a result of decades of conflict among armed groups and has created large-scale migration from rural to urban areas. Informed by the polymorphous model of sex work, which posits that contextual conditions shape the experience of sex work, we examined three main research questions. The first dealt with how internal displacement was related to the initiation of sex work; the second concerned the effect of agency on sex worker satisfaction; and the third examined how sex work in this context was related to HIV and other risks. Life history interviews were conducted with 26 displaced individuals who had done sex work: 14 were men who have sex with men and 12 were transgender women (natal males). Findings revealed that many participants began doing sex work in the period immediately after displacement, because of a lack of money, housing, and social support. HIV risk was greater during this time due to limited knowledge of HIV and inexperience negotiating safer sex with clients. Other findings indicated that sex workers who exerted more control and choice in the circumstances of their work reported greater satisfaction. In addition, we found that although many sex workers insisted on condom use with clients, several noted that they would sometimes have unprotected sex for additional money. Specific characteristics affecting the experience of sex work among the transgender women were also discussed.

Sex with sex workers among latino day laborers in Suburban Maryland.

Using the structural-environmental conceptual framework, this study employed mixed methods to address the question of whether sex with female sex workers contributes to HIV risk among male immigrant Latino day laborers in suburban Maryland. Because contextual factors can greatly affect HIV risk for both sex workers and their clients, this study investigated the organizational structure of sex work, factors that predicted men's hiring of sex workers, sexual behaviors performed with sex workers, and the use of condoms. Qualitative research was conducted to inform the development of a quantitative survey, but also provided crucial descriptions about the motivations, locations, arrangements, and sexual activities related to sex work. Key informant interviews (N = 10), in-depth interviews with day laborers (N = 10) and Latina female sex workers (N = 4), and two focus groups with day laborers (N = 11) were conducted, and a quantitative survey administered via Audio-enhanced Computer-assisted Self-interviewing (N = 174). Condom use was nearly universal in encounters with female sex workers, thus indicating that the sex workers were not an important source of HIV transmission in this context. Logistic regression was performed to test a model predicting sex with sex workers. Latino day laborers who reported more immigrant stress and who did not have a partner in the U.S. were more likely to have had sex with a sex worker, as were men who reported binge drinking. Structural and social conditions influenced the hiring of sex workers. Further research is warranted to better understand the interrelationships among these circumstances and to inform the development of programs to address them.

Armed conflict, homonegativity and forced internal displacement: implications for HIV among Colombian gay, bisexual and transgender individuals.

Colombia has endured six decades of civil unrest, population displacement and violence. We examined the relationships between contextual conditions, displacement and HIV among gay, bisexual and transgender individuals in Bogotá, Colombia. A total of 19 key informants provided information about internal displacement of sexual minorities. Life-history interviews were conducted with 42 participants aged 18 to 48 years and included questions about displacement experiences, sexual behaviour, life prior to displacement and participants' economic and social situation in Bogotá. The interplay of a variety of factors - including internal conflict and violence, homonegativity and 'social cleansing', gender and sexual identity and poverty - strongly shaped the varied experiences of displacement. Migration, sexual violence, exchange sex and low rates of HIV testing were risk factors that increased vulnerability for HIV in this displaced sample. Although displacement and HIV in Colombia are major problems, both are understudied.

Can additive measures add to an intersectional understanding? Experiences of gay and ethnic discrimination among HIV-positive Latino gay men.

The current study investigated a methodological question of whether traditional, additive, quantitative data can be used to address intersectional issues, and illustrated such an approach with a sample of 301 HIV-positive, Latino gay men in the United States. Participants were surveyed using A-CASI. Hierarchical logistic set regression investigated the role of sets of variables reflecting demographic characteristics, gender nonconformity, and gay and ethnic discrimination in relation to depression and gay collective identity. Results showed the discrimination set was related to depression and to gay collective identity, as was gender nonconformity. Follow-up logistic regression showed that both types of discrimination were associated with greater depression, but gender nonconformity was not. Gay discrimination and gender nonconformity were positively associated with gay collective identity, whereas ethnic discrimination was negatively associated. Results are discussed in terms of the use of traditional quantitative data as a potential means of understanding intersectional issues, as well as of contributing to knowledge about individuals facing multiple structural inequalities.

Popular perceptions of circumcision among Colombian men who have sex with men.

Male circumcision has received increased attention for its potential to reduce sexual transmission of HIV. Research on the acceptability of circumcision as a means of HIV prevention among men who have sex with men is limited. Men who have sex with men in Bogotá, Colombia, either participated in a focus group in which they shared information regarding their perceptions of circumcision or completed a survey that assessed circumcision experiences, attitudes, beliefs and willingness. Few participants reported they were circumcised, yet most participants reported knowing something about the procedure. Overall, attitudes towards circumcision were mixed: although circumcision was viewed as safe, it was also viewed as unnatural and cruel to babies. Beliefs that circumcision could improve sexual functioning and protect against STIs and HIV were not widely endorsed by survey participants, although focus-group participants discussed the potential impacts of circumcision on the availability of sexual partners and sexual performance. Some focus-group participants and many survey participants reported a hypothetical willingness to get circumcised if strong evidence of its effectiveness could be provided, barriers removed and recovery time minimised.

Sexual Role Identity and Anal Sex Positioning among Brazilian, Colombian, and Dominican Immigrant Sexual Minority Men.

Sexual role identities for anal sex and anal sex positionings are often conflated in research. This study aimed to identify profiles of sexual minority men based on sexual role identity and anal sex positioning and determine correlates of these profiles, including individual (i.e., HIV-status identity, condom use, partner type, sexual orientation) and cultural (i.e., same-race partnering, country of birth, acculturation) factors. A sample of Brazilian, Colombian, and Dominican immigrant sexual minority men (n = 480) living in New York City were surveyed about identity and positioning at the two most recent encounters. Individual and cultural factors were examined as correlates of profiles identified through latent class analysis. Four latent classes were identified: No Labels (12%), Receptive Bottoms (16%), Insertive Tops (23%), Insertive and Receptive Versatiles (49%). We found a concordance rate of ~70% between identity and behavior. A proportion (12%) of behaviorally versatile men chose not to use sexual role labels. Living with HIV was associated with receptive and versatile classes, sex with main partners was associated with versatility, and sexual orientation differed across classes. Identity and behavior should not be used interchangeably in research or applied domains, particularly given the complexities of versatility and men who prefer to not use labels.

Experiences of Violence and Mental Health Outcomes among Colombian Men who have Sex with Men (MSM) and Transgender Women.

Colombia endured 70 years of internal conflict, but despite a peace agreement, violence continues to be significant in the post-conflict era. Violence degrades the health and well-being of affected populations and it engenders psychological distress. Little is known about the impact of violence on the mental health of sexual and gender minority populations in Colombia. This study aimed to examine the frequency and sources of violence among cisgender men who have sex with men (MSM) and transgender women and their association with depressive symptoms and substance use. We administered a survey to 942 MSM and 58 transgender women recruited using respondent-driven sampling. We estimated the relationship between mental health indicators and experiences of violence using stepwise logistic and linear regressions, controlling for income, education, age, race, and mistreatment for being effeminate when younger. Respondent-driven sampling adjusted prevalence of any type of violence was 60.9% for the total sample, 59.8% for MSM, and 75.1% for transgender women. Experiences of violence were significantly related to depressive symptoms, binge drinking and drug use for the MSM sample. Violence perpetrated by family members or acquaintances was associated with greater depressive symptoms, and violence perpetrated by partners and strangers was associated with increased binge drinking and drug use. These results provide significant evidence of the negative association of experiences of violence and the mental health of sexual and gender minority people, a vulnerable population in Colombia. This study addresses issues of diversity regarding sexual orientation and gender identity in a Latin American middle-income country.

Identity and Relational Factors Associated with Sexual Role and Positioning for Anal Sex among Colombian Sexual Minority Men.

This study aimed to identify Top, Bottom, and Versatile sexual role identities and anal sex behavior profiles using latent class analysis in a sample of 942 sexual minority men living in Bogotá. A Versatile-insertive and receptive class (52.2%) was the most prevalent of the four resulting classes, whereas the least common was a class (1.7%) that did not use labels and had a low probability of anal sex. We examined whether identity and relational factors (i.e., sexual orientation, LGBT collective identity, and partner type) were associated with profiles. Gay identity was associated with versatile and receptive classes and bisexual identity was associated with insertive and versatile classes. LGBT collective identity was associated with the class characterized by Bottom identity and receptive positioning. Partner type was not associated with class membership, but versatile behaviors were more common among encounters with a main partner. Models using data at different timescales offered consistent patterns of behavior between the last encounter and the past three months, though the versatile class in the three-month model split into two classes based on frequency of versatile positioning. Findings highlight the relationship between sexual identity and positioning and can inform interventions for sexual health education and identity development.

Network analysis of PGD, PTSD and insomnia symptoms in Chinese shidu parents with PGD.

Background: Chinese shidu parents (bereaved parents over the age of 49 who have lost their only child) are potentially at a high risk of prolonged grief disorder (PGD), posttraumatic stress disorder (PTSD) and insomnia. Objective: The current study aimed to estimate three network models in 310 shidu parents who met the ICD-11 criteria for PGD: (1) a PGD network to identify central symptoms; (2) a comorbidity network to explore bridge symptoms between PGD and PTSD; (3) a comorbidity network to examine the associations between PGD and insomnia symptoms. Methods: The R-packages bootnet, qgraph and networktools were used to investigate the structure of network models and centrality indices of symptoms. In addition, robustness and significance analyses for the edge weights and the order of centrality were performed. Results: Emotional pain and numbness emerged as the most central symptoms in the PGD network. In the PGD-PTSD comorbidity network, the highest bridge strength symptoms were inability to trust others (PGD) and feeling upset (PTSD). Inability to trust others (PGD), avoidance (PGD), and impairment of life quality (insomnia) were possible bridge symptoms connecting PGD and insomnia. Conclusions: Reducing emotional pain and numbness may be a viable target in PGD interventions for shidu parents. Additionally, findings suggest that future studies could examine the role of inability to trust others and avoidance in PGD comorbidities. HIGHLIGHTS: • Emotional pain and numbness were the most influential symptoms in shidu parents with PGD. The role of PGD symptoms of inability to trust others and avoidance in the comorbidities of PGD with PTSD and insomnia might be worthy of further study.

Antecedentes: Los padres chinos shidu (padres en duelo mayores de 49 años que han perdido a su único hijo) tienen un alto riesgo potencial de presentar trastorno de duelo prolongado (TDP), trastorno de estrés postraumático (TEPT) e insomnio. Objetivo: El presente estudio tuvo como objetivo estimar tres modelos de redes en 310 padres shidu que cumplieron con los criterios CIE-11 para TDP: (1) una red TDP para identificar síntomas centrales; (2) una red de comorbilidad para explorar los síntomas puente entre TDP y TEPT; (3) una red de comorbilidad para examinar las asociaciones entre el TDP y síntomas del insomnio. Métodos: Se utilizaron los paquetes R bootnet, qgraph y networktools para investigar la estructura de los modelos de redes y los índices de centralidad de los síntomas. Además, se realizaron análisis de robustez y significancia para los pesos de borde y el orden de centralidad. Resultados: El dolor y el embotamiento emocional surgieron como los síntomas más centrales en la red TDP. En la red de comorbilidad TDP-TEPT, los síntomas fuerza de puente más altos fueron la incapacidad para confiar en los demás (TDP) y sentirse molesto (TEPT). La incapacidad para confiar en los demás (TDP), la evitación (TDP) y el deterioro de la calidad de vida (insomnio) fueron posibles síntomas puente que conectan el TDP y el insomnio. Conclusiones: Reducir el dolor y el embotamiento emocional puede ser un objetivo viable en las intervenciones de TDP para padres shidu. Además, los hallazgos sugieren que los estudios futuros podrían examinar el papel de la incapacidad para confiar en los demás y la evitación en las comorbilidades del TDP.

Cultural beliefs, partner characteristics, communication, and sexual risk among Latino MSM.

This study examined factors associated with communication about condom use and unprotected anal intercourse (UAI) in a U.S. sample of immigrant Latino MSM (N = 356), with a focus on culturally based beliefs. Logistic regression analysis revealed that communication about condom use at participants' most recent encounter was associated with a lower likelihood of UAI during that encounter. UAI was more likely when the partner was a main partner and there was seroconcordance. A separate logistic regression indicated that communication about condom use was less likely when the most recent encounter involved a main partner, greater sexual desire, and intoxication due to substance use. Although cultural beliefs were not predictive of communication about condom use or UAI at the most recent encounter, they were related to the occurrence of UAI in the previous three months. There is a need for more research on the interplay of culture, safer sex communication, and sexual risk.

Characteristics of Latino MSM who have sex in public settings.

Many men who have sex with men (MSM) have sexual encounters in public places, and some data suggest that this behavior is more common among Latino than non-Hispanic white MSM in the USA. In a sample of 482 Latino MSM born in Brazil, Colombia, and the Dominican Republic, and living in the New York City metropolitan area, we examined how demographic and psychosocial characteristics are related to having sex in public venues. Logistic regression was performed with the dichotomous outcome of sex in a public place in the previous six months. Demographic variables included education, HIV-positive serostatus, unknown HIV serostatus, and years in the USA; psychosocial variables included self-efficacy for safer sex, depression, and gay community involvement. Results indicated that those individuals with unknown serostatus were more likely than those with HIV-negative serostatus to have had sex in a public setting, as were men with lower self-efficacy for safer sex. These findings suggest that the partner pool may pose some risk to men who have sex in public sex venues, and therefore, low-risk sexual practices and condom use should be promoted in such settings. Contrary to expectations, higher education was related to sex in public settings, but neither depression nor more recent immigration was. Greater involvement in the gay community was also associated with having sex in public places, which may reflect the larger social function served by gay venues such as bathhouses and bars.

Present and past influences on current smoking among HIV-positive male veterans.

INTRODUCTION: Cigarette smoking has become an important influence of morbidity and mortality for HIV-positive individuals in the era of highly active antiretroviral therapy. Although smoking is common among military personnel and veterans, the lasting impact of military service on smoking at a later stage of life has not been examined. The current study investigated present and past influences on current smoking among HIV-positive male veterans. METHODS: Participants were 200 HIV-positive men served by the Veterans Affairs Medical Center. A survey was administered via audio-enhanced computer-assisted self-interview, and additional information was extracted from the computerized patient record system. RESULTS: Logistic regression was performed to test hypotheses concerning the participants' current situations as well as characteristics of their past military service. Having smokers in one's environment, being more depressed, and having used alcohol or drugs were associated with having smoked in the previous 30 days, whereas stronger endorsement of attitudes stating adverse effects of smoking was linked to lower likelihood of smoking. Neither having been in a military conflict nor the length of the military service was significantly related to current smoking. CONCLUSIONS: Remote experiences in the military did not have a sustained effect on smoking behavior years later. Implications of this study for the development of smoking cessation programs targeting HIV-positive veterans include the importance of altering attitudes about tobacco, treating underlying depression, addressing social influence, decreasing substance use, and increasing awareness of the heightened vulnerability to a variety of negative consequences of smoking among infected individuals.

Development and Evaluation of an Online Education-Entertainment Intervention to Increase Knowledge of HIV and Uptake of HIV Testing among Colombian Men Who Have Sex with Men (MSM).

Using a community-based participatory approach, we developed a film to promote HIV testing among young men who have sex with men (MSM) in Bogotá. Using a 5-step process to develop the intervention, we conducted 11 focus groups with MSM (n = 141) to receive community feedback at each step. To evaluate the intervention we recruited 300 young MSM to complete a baseline survey in December 2017. Between February-June 2018, 63 participants watched the film and completed a post-viewing survey, which showed the intervention was acceptable for the target population. Between August-December 2018, 48 MSM who watched the film and 47 who did not (control group) completed a follow-up survey. To obtain preliminary evidence of the efficacy of the intervention, we assessed the main effect of time (baseline vs. follow-up) and the interaction between time and group (intervention vs. control) on HIV testing uptake and intentions, and knowledge of HIV transmission dynamics and HIV-related rights. Knowledge of HIV rights increased from baseline to follow-up in the intervention group only. HIV Knowledge increased for both groups. HIV testing intentions increased significantly more for non-gay-identified men in the intervention group, but the overall effect of the intervention was not significant. Testing uptake did not change.

Stress and coping in HIV-positive former plasma/blood donors in China: a test of cognitive appraisal theory.

Throughout the 1990s, many villagers in rural China were infected with HIV through commercial plasma/blood donation. These former plasma/blood donors (FPDs) experienced many HIV-related stressors. This study tested a cognitive appraisal model of stress and coping in a sample of HIV-positive adult FPDs. Participants (N = 207) from multiple villages completed a battery of questionnaires assessing HIV-related stress, HIV symptoms, cognitive appraisal, coping behaviors, and psychological distress. Participants reported high levels of HIV-related stress, depression, and anxiety. In a structural equation model, greater HIV-related stress, HIV symptoms, and threat appraisal were directly associated with psychological distress. HIV-related stress was also indirectly associated with psychological distress through threat appraisal. In a second model, coping was found to mediate the relationship between challenge appraisal and psychological distress. Results support the utility of cognitive appraisal theory. Stress management interventions targeting HIV-positive FPDs in China are indicated.

Sex in public and private settings among Latino MSM.

Latino men who have sex with men (MSM) constitute a group at high risk for HIV. Recent approaches to understanding sexual risk have emphasized the role that contextual factors can play in shaping behavior. This study examined sexual behavior of Latino MSM in private and public settings. First, a within-person comparison of behaviors performed in sexual encounters that occurred in public and private settings was conducted. Unprotected anal intercourse (UAI) and other sexual behaviors involving anal stimulation were more common in private settings; group sex was more likely in public settings. Second, a between-person analysis compared sexual behaviors of MSM who went to three different types of public sex settings during the past six months. The types were: (1) commercial sex venues (CSVs), which were defined as businesses with the function of providing a space where MSM can go to have sexual encounters, such as gay bathhouses; (2) commercial sex environments (CSEs), which were defined as businesses with another apparent function, but in which MSM sometimes have sexual encounters, such as gay bars or pornographic movie houses; and (3) public sex environments (PSEs), which were defined as free public areas where MSM can go to find partners for anonymous sex, such as parks or public restrooms. Results indicated that anal sexual behavior was most likely to occur in CSVs and least likely in PSEs, but the probability of UAI was not found to differ among the three types of settings. Behavioral differences were discussed in terms of structural conditions related to privacy and safety, and psychological factors related to intimacy.

Partner selection among Latino immigrant men who have sex with men.

This qualitative study explored partner selection in a sample of immigrant Latino men who have sex with men (MSM). In-depth interviews were conducted with men living in the greater New York metropolitan area who had been born in Brazil (n = 10), Colombia (n = 14), or the Dominican Republic (n = 9). One focus group was conducted with MSM from each of the three countries (9 Brazilian, 11 Colombian, and 5 Dominican participants). A grounded theory approach revealed three main themes relating to partner selection. The first concerned stereotypes of how Latino and Anglo-American men tend to behave in their sexual encounters and relationships. The participants perceived Latinos to be more affectionate and passionate, whereas they saw Anglo-American men as more independent and practical. These cultural discrepancies sometimes resulted in a preference for Latino partners. A second theme concerned stereotypes of the national groups, including expectations that Brazilians would be sexy and sensual and that Dominicans would have large penises. As found in other research on MSM of color, ethnic and national stereotypes were associated with experiences of sexual objectification. The third theme addressed the importance of masculine characteristics in sexual attraction and partner selection. Negative feelings towards effeminate men who did not conform to normative male physical or behavioral presentation reflect a stigma found inside and outside of the gay community. These findings suggest that gender and ethnic stereotypes play an important role in shaping partner choice and have implications for sexual risk and relationship formation.