Introduction

At any given time, an estimated 6.3 million people are sex trafficked globally [1]. In the United States (U.S.), sex trafficking is defined by the Trafficking Victims Protection Act of 2000 as “the recruitment, harboring, transportation, provision, obtaining, patronizing, or soliciting of a person for a commercial sex act [2].” Notably, the elements of force, fraud, or coercion must be present when the commercial sex act involves an adult; however, force, fraud, or coercion is not required if a minor is involved in the commercial sex act [2]. The number of individuals who have been sex trafficked in the U.S. is unknown. Available data typically combines labor and sex trafficking, and is restricted to hotline reports, arrests, and legal proceedings, which encompass only a fraction of the problem. One example is the National Human Trafficking Hotline annual summary, which shares national and state-specific data on all communications to provide a glimpse into the number of individuals who may be trafficked in the U.S. The annual summary reports: 1) signals, which are communications received via a hotline call, online report, web chat, SMS, or email; 2) cases, which represent a distinct situation that can involve one or more potential victims of trafficking reported to the hotline through one or more signals; and 3) victims, which are individuals involved in one or more cases. The National Human Trafficking Hotline also counts the tips received about potential situations of sex and/or labor trafficking from signals, as opposed to signals requesting information and resources. The latest available summary from the National Human Trafficking Hotline for 2024 reported receiving 8,024 signals from victims or survivors of human trafficking, 11,999 cases were identified, and 21,865 victims were involved in these cases [3]. Texas had the second-highest percentage of total signals (7.5%) and total cases (11.3%) next to California [3]. In 2024, the hotline received 1,094 tips about potential situations involving trafficking in Texas, and 68% of those involved sex trafficking [3]. Similar data for more specific regions or cities within Texas do not exist, however, one report estimated that there were over 14,500 victims in the greater Houston area in 2019 [4]. Data from law enforcement response and human trafficking cases in federal court, indicate that age and gender are factors contributing to vulnerability, as female youth and young adults comprise most sex trafficking victims [5,6]. Available sources can provide insight into potential victims and survivors of sex trafficking, or those that make it to the court system but none provide an estimated prevalence in general or subpopulations. It is critical to better understand the problem in a large urban area like Houston, Texas among the most vulnerable populations.

In the 2024 U.S. Department of Housing and Urban Development (HUD) Annual Homeless Assessment Report, the point-in-time count estimated that there were over 38,000 unaccompanied youth on a single night in the U.S [7]. The McKinney-Vento Act of 1987 provides the foundation for the definition of homelessness among youth or young adults, which includes those “who lack a fixed, regular and adequate nighttime residence” as well as those sharing housing with other persons (doubled-up), living in temporary accommodating such as motels, places not designed for sleeping, and migratory children [8]. The application of this definition has changed over time. While the HUD narrowed the definition by restricting individuals “doubled up” for housing eligibility purposes (inclusive of the HEARTH Act amendments) [9], the Department of Education retains a broad definition to identify and support students in schools. Generally, the definition used by the Department of Education reflects a broader spectrum of housing instability among youth and is more likely to capture youth who may need a variety of supportive services. Youth who are unstably housed tend to lack basic needs such as food, shelter, and protection, making them more vulnerable to sexual exploitation, which legally constitutes sex trafficking when the individuals involved are minors [10–13]. Numerous studies have documented sex trafficking victimization rates between 11–41% among youth experiencing homelessness (YEH) across various U.S. regions, including Atlanta, Kentucky, and Arizona [10,14,15]. Efforts to develop and deploy consistent trauma-informed screening tools for YEH are ongoing but are not yet widely implemented [16,17].

YEH face elevated risk for sex trafficking due to intersecting structural and interpersonal vulnerabilities. [14]. Histories of abuse, family conflict, foster care involvement, housing instability, and adverse childhood experiences have all been associated with increased vulnerability to sexual exploitation and trafficking [14,18]. Traffickers often exploit unmet needs for safety, housing, emotional support, and financial resources, while limited access to trauma-informed services may further increase risk and reduce opportunities for intervention. [13,14]. These findings are consistent with evidence from migrant populations, where traffickers exploit housing instability, economic hardship, immigration-related fears, and social marginalization to maintain control over victims [19].

Despite increasing recognition of the link between homelessness and sex trafficking, significant gaps remain in understanding the prevalence and specific characteristics of trafficking survivorship among YEH. Moreover, few studies have disaggregated findings to examine the diverse experiences of youth based on race, gender, foster care system involvement, and substance use. This lack of nuanced data hinders the development of tailored prevention interventions and policies that can address the complex realities of trafficked youth. To address this gap, the current study examined the prevalence and characteristics of sex trafficking among a sample of YEH in Houston, Texas, a city with high reported rates of trafficking and a large, diverse unhoused youth population. By examining demographics, experiential factors, and behavioral factors, this study aimed to inform trauma-informed, accessible approaches to prevention and care [20].

Methods

Results

Demographics

The median age of participants was found to be 21 years (interquartile range = 4; 19–23 years). In this sample, 23.1% reported experiencing sex trafficking. Table 1 describes the responses to each of the five items from the Commercial Sexual Exploitation (CSE) domain of the Human Trafficking Screening Tool.

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Table 1. Sex trafficking experiences (N = 450).

https://doi.org/10.1371/journal.pone.0357091.t001

Based on the responses, it was also found that around 27.4% of the participants reported experiencing sexual assault, while 23.6% reported as having traded for sex in their lifetime. Types of drug use is presented in Fig 1. Nearly one half (48.2%) of participants reported using Marijuana in the past 30 days. Use of hallucinogens, inhalants, crack, speedball, heroin, cocaine, methamphetamine, amphetamine, and barbiturates was low, ranging from 1.6% to 5.5%.

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Fig 1. Past-30-day substance use among youth experiencing homelessness in Houston, Texas.

Percentages represent the proportion of participants reporting use of each substance during the previous 30 days.

https://doi.org/10.1371/journal.pone.0357091.g001

Bivariate analysis

Results from the univariate Modified Poisson regression analysis are presented in Table 2. Among respondents who self-identified as having experienced sex trafficking, 63.5% identified as female, 59.6% reported some form of drug use in the previous 30 days, and 60.6% identified as Black. Gender was found to be a statistically significant predictor, with females (PR = 2.53, 95% CI 1.682–3.812) and other gender (PR = 2.12, 95% CI 1.050–4.293) having higher prevalence of experiencing sex trafficking (PR = 1.69, 95% CI 1.171–2.426). Participants with a history of foster care had increased prevalence (PR = 1.53, 95% CI 1.067–2.189) of experiencing sex trafficking compared to those with no foster care experience. Lastly, having a last permanent residence within Houston had lower prevalence of experiencing sex trafficking compared to someone who did not have their residence within Houston; however, this association was not found to be statistically significant (PR = 0.74, 95% CI 0.523–1.045). Age, drug use in the last month, and race/ethnicity were found not to have significant bivariate associations with sex trafficking.

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Table 2. Bivariate associations with sex trafficking.

https://doi.org/10.1371/journal.pone.0357091.t002

Adjusted Analysis

Results from the multivariable modified Poisson regression analysis are presented in Table 3. After adjusting for other predictors, female study participants had higher prevalence than male participants of experiencing sex trafficking (aPR = 2.341, 95% CI 1.530–3.582). Age, ethnicity, sexual orientation, drug use, Houston residency, and history of foster care were not statistically significant predictors, although foster care approached statistical significance (aPR = 1.416, 95% CI 0.990, 2.025).

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Table 3. Associations with sex trafficking in adjusted analysis.

https://doi.org/10.1371/journal.pone.0357091.t003

Discussion

Nearly one in four YEH in this sample reported experiences consistent with sex trafficking, highlighting the substantial burden of exploitation among youth accessing homelessness services in Houston. Female-identifying youth were disproportionately affected, with significantly higher prevalence of reporting experiences consistent with sex trafficking than male-identifying youth. Our findings are consistent with prior research, that cisgender women are disproportionately represented in detected cases of sex trafficking among YEH in the U.S. [15,24,25]. While the current findings generally align with global patterns [26,27], reliance on current methodologies likely underestimates trafficking by gender across YEH sub-groups [24,26–28].

In our study, having a history of foster care involvement was not statistically significant in the adjusted analysis; however, evidence from prior studies indicate youth with prior foster care involvement are at an increased risk of sex trafficking [14,29]. Homelessness, along with other factors such as abuse history and juvenile justice involvement, have been shown to contribute to this vulnerability in other samples [24]. This study may not have found a statistically significant association because we only measured the history of foster care, while other studies documented that the length of time or number of placements in foster care were associated with increased vulnerability to experiencing sex trafficking [18,29]. Race was not a significant predictor of sex trafficking, which is inconsistent with recent studies that have reported that a substantial proportion of people experiencing homelessness have been from the Black and Hispanic communities [15,30].

Youth who identified as LGBTQ+ in our sample showed a higher prevalence in bivariate analysis, although this association was not statistically significant in the adjusted model. This pattern may reflect overlapping vulnerabilities well-documented in the literature, including stigma, family rejection, discrimination, homelessness, and survival sex. LGBTQ+ youth experience disproportionate rates of homelessness and are significantly more likely to engage in sex exchange to meet basic needs such as food, shelter, or safety [31,32]. Among YEH, LGBTQ+ individuals have been found to have more than twice the prevalence of being sex trafficked compared to heterosexual peers and to report higher rates of prior sexual assault, substance use, and suicide attempts [31]. Similarly, research among LGBTQ+ youth in out-of-home care highlights survival sex as a response to intersecting social exclusion, economic precarity, and systemic transphobia [32]. Research also emphasizes that LGBTQ+ individuals, especially those facing homelessness or migration, remain among the most hidden victims of sex trafficking globally due to stigma and underreporting [33]. The decrease in the association in the adjusted model likely reflects confounding effects due to other social determinants, such as gender and foster care involvement, both of which disproportionately affect LGBTQ+ youth. These findings reinforce the need for inclusive, trauma-informed, and affirming services that address the compounded risks of sexual, and gender minoritized youth within homelessness and child welfare systems.

Being a Houston resident (last permanent housing was in Houston) was not associated with experiencing sex trafficking. It is possible that the last permanent housing did not capture the migratory nature of the YEH in this sample. Substance use was also not associated with being sex trafficked, even though the relationship between substance uses and sex trafficking has been documented in various ways, including playing a role in survival sex, coercive sex, and sexual trauma [25,34]. Additional research is needed in this area to examine the potential for increased vulnerability of YEH for risky behaviors, including substance use, substance use during sex, and need-based sex [34]. Migratory YEH may be more disconnected from social relationships and resources, leaving them more vulnerable to being sex trafficked.

Our findings suggest that nearly one in four YEH have experienced sex trafficking. This underscores the urgent need for systems of care, including homeless shelters and service providers, to implement standardized intake protocols that screen for human trafficking. Evidence from a Houston shelter shows that using a trafficking-specific screener identifies substantially more sexual and labor exploitation, and key risk factors, than routine psychosocial face-to-face assessments [13]. The Urban Institute’s Human Trafficking Screening Tool (HTST), designed for youth involved in child welfare and homeless youth services, is one of several tools recommended for these settings [13]. Accordingly, we encourage adoption of the HTST as part of service intake workflows. Service providers across shelters, drop-in centers, and health care settings should also be trained to recognize indicators of exploitation and to respond with trauma-informed care. Trauma-Focused Cognitive Behavioral Therapy (TF-CBT) has demonstrated feasibility and clinically meaningful reductions in PTSD symptoms when embedded within shelter services for YEH [35].

Beyond service-level changes, prevention outreach should extend to transportation hubs, transitional housing, and migration corridors where youth may be disconnected from protective networks, and into digital spaces. Young people frequently encounter and seek health information on social platforms (e.g., Facebook, YouTube, Instagram), suggesting these channels can be leveraged for outreach and education [36]. At the same time, social media is documented as a venue for trafficking recruitment and communication; hotline data show recruitment across mainstream platforms (e.g., Facebook, Instagram, Snapchat), while survivors report using social media both during exploitation and to reconnect with support [37]. Prevention and treatment outreach strategies should therefore pair digital safety messaging with credible, youth-centered content in the spaces YEH already uses [38].

Policy efforts should prioritize prevention interventions that address transitions out of foster care, histories of sexual violence, and gaps in housing and social services, especially for youth that are new to a community. Research has also highlighted provider bias in their responses to trafficking manifests at multiple levels, through stereotyping and structural barriers, and underscores the urgent need for holistic interventions in prevention, treatment, research, and policy [39]. Future research should employ longitudinal and advanced modeling approaches, such as structural equation modeling, to better understand causal pathways and mediating factors in sex trafficking. Importantly, researchers should disaggregate data to reveal patterns of marginalization and ensure that prevention and treatment interventions are tailored to the specific realities of diverse youth.

Conclusion

In this cross-sectional study of YEH in Houston, Texas, nearly one in four participants reported experiences consistent with sex trafficking, with significantly higher prevalence among female-identifying youth. These findings highlight the profound influence of structural inequities, including unstable housing, gender-based vulnerability, and limited access to supportive services, on risk for exploitation. Efforts to address trafficking among YEH should operate across structural, organizational, and interpersonal levels. Practice and policy should prioritize routine, trauma-informed screening using validated tools in shelters, drop-in centers, and healthcare and social service settings. Furthermore, service providers should be equipped to identify, engage, and support youth at risk for or with histories of exploitation through coordinated, survivor-centered approaches that strengthen pathways to safety, stability, and care.

Acknowledgments

We are grateful for the invaluable contributions of our community partners, whose collaboration and commitment to serving this population are essential to this research.