SIBLING SUPPORT FOR TRANSGENDER AND GENDER DIVERSE YOUTH: A SCOPING REVIEW

Abstract

Purpose

Sibling support for transgender and nonbinary (TNB) youth has the potential to improve TNB youths’ mental health.

Methods

A scoping review was conducted to map the knowledge of TNB youths’ sibling relationships to create a foundation for the development of sibling-based support interventions for TNB youth.

Results

Nine included articles covered two areas: TNB youths’ perceptions of sibling support (n=5) and cisgender siblings’ lived experience with a TNB sibling (n=4). Siblings were perceived to support TNB youth, and their support was associated with less depression, suicidal ideation, and externalizing problems. Siblings of TNB youth lacked knowledge of TNB identities and support for their own understanding and acceptance. Siblings may experience unique stressors around their TNB sibling’s changing gender identity. Overall, having a TNB sibling was perceived as a positive experience. None of the studies included intervention with or for siblings of TNB youth.

Discussion

Sibling support can be helpful for TNB youths’ mental health. However, cisgender siblings’ unique needs are rarely addressed. Providing cisgender siblings with knowledge of TNB identity, a place to process fears and concerns, and skills to navigate situations that may arise in relation to their sibling’s gender, has the potential to benefit both siblings.

IMPACT STATEMENT

This synthesis of the emerging knowledge on sibling support of transgender and nonbinary young adults highlights important gaps in the state of the science, the potential benefits of sibling support, and the unique needs of cisgender siblings, which could inform the development of a sibling-based support intervention.

INTRODUCTION

Youth who are transgender (i.e., those who have a gender that is different from the sex they were assigned at birth) and/or nonbinary (i.e., those who have an expansive gender that is not within a binary of girl/boy or have no gender at all) (TNB) are at increased risk for adverse mental and physical health outcomes due to pervasive societal stigma and discrimination.^1–3 Family support for TNB youth is known to buffer effects of discrimination and violence, resulting in lower levels of psychological distress,^4,5 emotional distress,^6,7 and fewer depressive symptoms.^8,9 Among respondents in the United States Transgender Survey, those who rated their families as supportive were less likely to experience severe mental distress than those who experienced familial rejection.¹⁰ However, while much of what is known focuses on parents and general family support, there is limited information on sibling support specifically.^8,11–13

Although family support has been associated with numerous positive outcomes for TNB youth, parental and sibling responsibilities in providing guidance in information-seeking and skill-building processes for TNB adolescents have been largely unexamined.^14,15 This is especially true for TNB youth from underserved racial/ethnic communities, who have been often overlooked in this area of research.¹⁶ Existing family-based interventions for cisgender adolescents cannot simply be modified for transgender adolescents because the latter’s gender identity and behaviors are differently affected at multiple systemic levels, including their families of origin, peers, schools and the larger community.¹⁷ Further, identities, emergent attractions, and sexual activities involving transgender adolescents are not always supported by these social systems.

Sibling relationships are often central to human development^18,19 and can serve as an enduring protective factor against negative mental health across the lifespan.^20–24 Siblings may reach TNB youth early to provide time-sensitive information and support that is responsive to their questions and anticipated needs, consistent with findings in siblings of gay, lesbian, and bisexual (LGB) youth.^25,26 Additionally, with TNB adolescents living at home and disclosing their gender identities at younger ages compared to previous cohorts,²⁷ trusted family members such as siblings are optimal sources of support and wellness promoters. Aside from extended opportunities for sibling influence, siblings may often be more affirming than parents.^28,29 With the growing evidence that focuses on cisgender siblings as comparison groups for mental health outcomes^30–35 and a collection of studies focused on TNB youths’ perceptions of their siblings’ support²⁸ and its effect on mental health outcomes,^36,37 there is a need to systematically investigate the ways in which siblings may directly or indirectly impact TNB youths’ health outcomes. As such, we conducted a scoping review to synthesize the literature as a basis for creating future research and clinically meaningful work. Scoping reviews may be used to map the current evidence and gaps in a field of study and are particularly useful when examining emerging evidence. Rather than seeking to answer a specific question as in a systematic review, a scoping review provides a broad overview of the types of evidence and relevant findings available for the topic.³⁸

METHODS

Literature Search

A search strategy was developed in collaboration with a reference librarian at the Johns Hopkins University Welch Medical Library to capture articles that included sibling relations and TNB youth. MeSH terms, when available, were searched for siblings, sibling relations, adolescent, young adult, child, and transgender persons. Otherwise, searches were restricted to titles and abstracts using the following algorithm: “sibling relations” OR “siblings” OR “sibling*” OR “brother*” OR “sister*” AND “adolescence+” OR “child*” OR “teen*” OR “youth*” OR “teen*” OR “adolescen*” AND “transgender persons+” OR “transgender*” OR “transsexual*” OR “two spirit” (see supplemental document 1 for search terms). Four electronic databases (PubMed, Web of Science, CINAHL Plus (Ebsco), and PsycINFO) were searched for articles published before May 2023.

Article Screening

All search results were then uploaded into Covidence³⁹ for screening and review. Titles were initially screened in Covidence³⁹ to exclude manuscripts that were not related to TNB youth and their siblings (e.g., articles focused on cancer) and/or not conducted among TNB youth. Included abstracts were then reviewed by at least two authors (conducted by authors MK, JB, and RS) to ensure they met inclusion criteria: 1) sample included TNB children and young people (6–29 years – defined as “youth”) and focused on actual or perceived support from or relationships with siblings and/or family units OR 2) siblings (full, step, foster, etc.) or family units of TNB youth and was focused on their needs, experiences, and relationship(s) with the TNB youth, and was 3) written in English, and 4) either a peer-reviewed article, conference abstract, or dissertation focused on original research articles. Articles were excluded if they were 1) solely focused on parent-child relations, 2) either used siblings only as comparison groups only or didn’t focus on relationships between siblings and TNB youth, 3) did not disaggregate TNB youth from larger LGBTQ samples, 4) did not disaggregate youth (ages 6–29) from other age groups in older TNB samples, and/or 5) did not disaggregate findings about siblings from other family members. Abstract review discrepancies were resolved by consensus among all three reviewers. An ancestry search of reference lists was conducted to identify any relevant citations that may have been missed in the original search and improve comprehensiveness.⁴⁰ Finally, three researchers with recent or ongoing work who have published about sibling relationships among LGBTQ youth were emailed directly to see whether they had any relevant findings to include (i.e., “gray literature”).

Data Extraction

Two authors (MK & JB) extracted data from each of the included articles into an Excel spreadsheet. Extracted data included: author names; year of publication; location(s) of the study; study objectives/purpose; model/theoretical approach; population; study design/approach; outcomes; a concise description of the authors’ findings; limitations, and other notes. When family members other than TNB youth and/or their sibling(s) were included in the study, only data related to siblings were extracted.

RESULTS

After removing duplicates, 132 titles were screened with 113 excluded because they did not meet inclusion criteria. Eighteen full-text articles were reviewed, and two additional articles were added (one each through ancestry search and gray literature). Nine articles were included in the review. A literature flow is presented in Figure 1. The most common reason for exclusion (n = 8) was a focus on participants who fell outside of the specified age range (6 to 29 years) or a failure to disaggregate results by age group when multiple age groups were present. The nine articles in the review included samples from seven unique studies.

Figure 1.

Literature Flow

Sample Recruitment.

Five samples were recruited from the US (two national, three Northeast);^{28,36,37,41,42} two were recruited from Australia,^43,44 and one was recruited from England.⁴⁵ Samples were recruited mainly through community-based groups (n=3),^42–44 gender affirming services or clinicians directly (n=2),^37,45 a combination of community and clinical settings (n=1),⁴¹ and online (n=1).³⁶ Recruitment materials were directed at TNB youth and/or their siblings,^28,36,42 through parents,^37,44,45 and through a combination of the two strategies.^41,43

Sample Composition.

Three samples included multiple family members,^37,41,44 three focused exclusively on cisgender siblings of TNB youth,^43,45 and three included only TNB youth.^28,36,42 Among the six samples that mean age was available (or could be calculated), TNB youth’s average age ranged from 14.6 – 21.5 years. Three samples included transgender and nonbinary TNB youth with a range of gender identities,^28,36,41 one included only TNB youth assigned male at birth,⁴² one included only transmasculine and transfeminine TNB youth.³⁷ Among studies that included data directly from siblings, they were predominantly cisgender, older, biological siblings with more sisters (n=26) than brothers (n=21). Siblings’ mean ages ranged from 14.4–21.1 years. In a few instances, a sibling either reported on more than one TNB sibling⁴³ or multiple siblings shared their experiences about a single TNB sibling.⁴⁵

Theoretical and Methodological Approaches.

A range of theoretical approaches were used to frame studies and their subsequent analyses, including: Interpersonal Acceptance-Rejection Theory,^28,36,37 Minority Stress Theory,⁴¹ Stage Model of family transition,⁴³ Life Course Theory,⁴² and Community Psychology Perspective,⁴⁵ Ecological Systems Theory,⁴⁶ Family Systems Theory,⁴⁶ and Theory of Social Stigma.⁴⁶ Four of the articles were quantitative,^28,36,41,42 four were qualitative,^43–46 and one used mixed methods.³⁷ Among the quantitative analyses, two described siblings’ support,^28,42 and three sought to explain relationships between siblings’ acceptance and TNB youths’ mental health.^36,37,41 All four of the qualitative studies explored cisgender siblings’ needs and experiences surrounding their TNB sibling’s identity disclosure.^43–46 The main findings of each of the included studies are presented in Table 1.

Table 1.

Summary of Included Literature

First author, year	Location	Sample Recruitment & Characteristics	Focus	Results
Siblings’ Perceived Support
Nuttbrock et al., 2009	Northeast US	333 TNB individuals (19–39)a who were AMAB; recruited from the community in New York City	Provide qualitative description of GID affirmation in context of lifecourse	- Respondents selectively disclosed GID to their sibling(s) - 94 had disclosed their GID to a sibling during adolescence; 20.2% were never treated the ‘way they wanted to be treated’ with regard to gender - Across the life course, gender affirmation from siblings increased
Bosse et al., 2022	US	TNB youth (18–25 years) with at least one sibling ≥18 years who knew their gender identity; recruited online 348 GDY (Mage= 21.5 years)  108 nonbinary; 102 transgender;  80 another gender; 38 genderqueer;  17 man; 3 woman Siblings predominantly bio (74%), older than respondent (66%); woman (53%); heterosexual (51%)	Compare TNB youths’ perception of sibling and parental acceptance-rejection at the time of GID disclosure and time of the survey	- Majority of TNB youth perceived sibling relationship to be the same or better following GID disclosure - Siblings were perceived to be significantly more supportive of GID than either parent immediately following GID disclosure and at time of survey - Cis F siblings were more supportive than Cis M siblings at time of survey, but not immediately post-disclosure - LGBQ siblings were significantly more supportive than heterosexual siblings immediately after disclosure and at time of survey - Perceived SbA not associated with birth order, relationship type, living with sibling at time of survey, number of siblings, or time since GID disclosure
Sibling’s Acceptance and TGD Young People’s Mental Health
Katz-Wise et al., 2018	Northeastern US	Families with TNB youth (13–17 years) recruited from community and clinical settings in New England 33 TNB youth (Mage=15.2 years)  17 transmasculine; 12 transfeminine; 4 nonbinary 15 cisgender siblings (Mage=17.9 years)  7 girls/women; 8 boys/men	Describe associations between TNB youth mental health and family members’ reports of family functioning (communication and satisfaction)	- Only TNB youths’ own perception of family functioning was associated with self-harm, DEP and ANX symptoms, self-esteem, and resiliency - NS difference between TNB and Cis siblings’ family satisfaction
Pariseau et al., 2019	Northeastern US	TNB youth seeking gender-affirming care at a children’s hospital in Boston 54 TNB youth (Mage=14.6 years)  30 Transfeminine  24 Transmasculine 87% had a sibling (Mage=15.5 years)	Document TNB youth experiences of acceptance-rejection by family members and examine relationships between family members’ acceptance-rejection and GDY psychosocial functioning	- Sibling acceptance (SbA) varied; majority in high acceptance/low rejection - SbA was associated with less externalizing problems (r=−52, p=.004) and SI (r=−.51, p=.005), but not associated with DEP, ANX, or internalizing problems - in multivariate analysis, SbA explained 30% of the variance in SI - increased SbA was associated with decreased likelihood of SI (OR=.2)
Bosse et al., 2023	US	TNB youth (18–25 years) with at least one sibling ≥18 years who knew their gender identity; recruited online 286 GDY (Mage= 21.5 years)  87 Nonbinary; 85 transgender; 65 another gender; 36 genderqueer;  13 man; 2 woman Siblings predominantly bio (74%), older than respondent (63%); woman (52%); heterosexual (51%)	Evaluate associations between perceived familial acceptance-rejection and DEP and suicidality among GDY and explore whether SbA moderates associations between parental acceptance and GDY mental health	- Considered independently and in the context of parental acceptance-rejection, SbA is associated with GDY DEP symptoms - Sibling rejection on its own was associated with increased odds of reporting lifetime SA and past year SI - SbA did not moderate the association between parental acceptance-rejection and GDY mental health; however, each additional family member high in rejection was associated with a 6-point increased in DEP score and 1.5–3x higher odds of reporting lifetime or past year suicidality
Needs and Experiences of Siblings of GDY
Wheeler et al., 2019	England	Cisgender siblings (11–25 years) with a TNB sibling 8–18 years); recruited primarily through clinicians with materials directed at parent/family 8 cisgender siblings (Mage=15.3 years)  6 sisters, 2 brothers  Predominantly biological siblings; 2 siblings are reporting on a shared  GD sibling	Explore the experiences of siblings of gender diverse individuals and identify potential support needs of siblings of GD individuals	- All felt relationship with TNB sib had improved - Significant fears for TNB sib: concerns about their physical safety (in society), potential side effects of GAT; and whether TNB sib will be able to find a partner or be a parent - Some relationship tension when cis sibs felt their TNB sibling did not recognize how challenging it was for them to adjust - A few (cis) siblings resentful of family resources (time and money) being used for gender transition - Five key stages in a process of adjustment:  1. Confusion following GID disclosure/discovery  2. Social transition and sibling involvement (i.e., helping pick TNB sibling’s new name) was helpful for gaining clarity  3. Managing TNB siblings’ two identities (e.g., using one name at home, one in public; remembering who outside the family knows the about sibling’s GID); created fear about consequences of accidental disclosure to others  4. Deeper empathy for TNB siblings brought on by acceptance  5. Reflections on sibling experience-appreciate new knowledge of TNB issues/diversity in general
Westwater et al., 2020	AUS	Cisgender siblings (13–17 years) of TNB young people (12–17 years) with gender dysphoria; parents of youth with gender dysphoria were recruited online via parent-focused list-serves 8 cisgender siblings (Mage=14.4 years)  6 brothers, 2 sisters	Identify, describe and interpret individual family member experiences of youth gender diversity	- All siblings reported benefits of having a TNB siblings, including improved knowledge/insight, stronger family relations, and overall positive emotional experiences - Siblings underwent their own transition/adjustment process; relationships changed during that time - Common worry was about how people outside the family would react - More than half (n=6) reported experiences of discrimination/microaggressions related to their sibling’s TNB identity - Some siblings (n=3) felt they were treated differently by others - Most siblings (n=6) had never been involved in gender-related specialist appointments with their TNB sibling; nearly all were interested and thought it could be beneficial for understanding as well as to obtain own support if needed
Parker & Davis-McCabe, 2021	AUS	Cisgender siblings (14–26 years) of a TNB individual; recruited through LGBTQI+ community group, friend, or family member 17 cisgender siblings (Mage=21.1 years)  11 sisters, 6 brothers  13 full siblings; 4 half siblings; 1 person reporting on 2 GD siblings	Explore the societal and relational experiences and needs of siblings of trans people	- Overarching theme: responsibility to support and protect; however, it took some siblings time to come to this realization - Societal issues: lack of access to information, lack of visibility, feelings of isolation, lack of formal support - Relationship with TNB sibling: negotiating changes; holding the knowledge; witnessing negative experiences; building authenticity - Family/social relationships: gender transition impacts whole family; acting as intermediary; family relationships and LGBTQI+ community as sources of support; relational strain and decisions whether to cut-off people unsupportive of TNB sibling
Godwin, 2024	Northeastern US	Invited to take part in a longitudinal study of families with TNBb youth (1317 years) recruited from community and clinical settings in New England 15 cisgender siblings (Mage=17.9 years; range: 13–24)  7 girls/women; 8 boys/men	Explore the experiences of siblings of TNB youth following disclosure and navigating family and community responses (Wave 1 data)	- Identified three main themes: anticipating identity; peri-and post-disclosure family dynamics; and assessing responses to their sibling - Traditional gender stereotypes, and TNB sibling’s adherence to them, influenced whether cisgender siblings anticipated or were surprised by gender identity disclosure as well as informed postdisclosure expectations - Majority wanted more information and wanted to be more involved in the process (especially older siblings) - Lack of resources/parent availability for cisgender siblings following TNB identity disclosure - Improved feelings of closeness with TNB siblings following disclosure - Expressed concerns for TNB siblings’ safety and felt protective of them; some concerned that they would be treated differently by others for having a TNB sibling

Abbreviations: AMAB: Assigned male at birth; ANX: anxiety; AUS: Australia; Cis F: Cisgender Female; Cis M: Cisgender Male; DEP: Depression;; GAT: gender-affirming treatment; GID: Gender Identity; LGBTQI+: Lesbian, gay, bisexual, transgender, queer, intersex, other diverse sexual orientations; SbA: Sibling Acceptance; SI: Suicidal Ideation; TNB: transgender and/or nonbinary; UK: United Kingdom; US: United States

^areporting focused on younger cohort; larger study includes 571 AMAB folks

^bauthors requested use of this acronym in favor of language that represented participant identities

Describing Siblings’ Perceived Support

The two descriptive studies characterizing siblings’ support for gender identity reported that siblings were generally supportive and that siblings’ support for TNB individuals increased over time.^28,42 Sibling characteristics such as assigned sex at birth and sexual orientation were associated with siblings’ amount of support for gender identity. Female siblings were perceived to be more supportive of gender identity than male siblings and siblings with a lesbian, gay, bisexual, queer, or other sexual minority identity were perceived to be more supportive of gender identity than heterosexual siblings.²⁸ However, other characteristics such as birth order and number of siblings were not associated with siblings’ support for gender identity.²⁸

Sibling’s Acceptance and TNB Youth Mental Health

All three explanatory studies evaluated associations between levels of family members’ acceptance in association with TNB youths’ mental health, including depression, anxiety, internalizing and externalizing behaviors, self-harm, and suicidality. TNB youth’s positive perception of family functioning was associated with better mental health (i.e., higher self-esteem and resilience).⁴¹ TNB youth reporting better family functioning⁴¹ and higher levels of sibling acceptance ^36,37 scored lower on measures of depression. Likewise, perceived sibling acceptance was associated with decreased suicidal ideation^36,37 and fewer externalizing symptoms (e.g., aggression), but not decreased internalizing problems (e.g., depression) or anxiety.³⁷

Cisgender Siblings’ Experiences and Needs

All four qualitative studies were focused on the needs and the familial, societal, and relationship experiences of cisgender siblings of TNB youth.^43–46 Two studies highlighted that adjusting to their siblings’ identity was a process that took time,^44,45 with participants in one study estimating the adjustment process to last between three to six months.⁴⁵ Traditional gender stereotypes played a role in cisgender sibling’s expectations of their TNB sibling. Those whose TNB sibling had displayed nonconforming behaviors and attributes for their assigned sex at birth expected the TNB sibling’s disclosure rather than being surprised by it.⁴⁶ Meanwhile, confusion and/or lack of information about TNB gender identities was acknowledged in three studies.^43–45 Knowledge about transgender issues was a double-edged sword; too much knowledge was deemed as overwhelming and, in some cases, brought on additional concerns for their TNB sibling (e.g., about their physical safety).^43,45 Some cisgender siblings expressed concern about the safety and potential side effects of gender-affirming medical care (GAMC)⁴⁵ and interest in direct involvement in assisting with social transition.^45,46 Others expressed interest in involvement in medical appointments, including the opportunity to receive their own support when needed.⁴⁴ Importantly, lack of formal support and resources for cisgender siblings were identified in all four studies.^43–46

As part of relationship changes post-disclosure, some cisgender siblings felt their TNB sibling did not recognize how difficult adjusting was or did not seem to acknowledge the amount of family resources being put into their transition.⁴⁵ Siblings also perceived a change in relationship with one or more parents due to additional time investment in addressing the psychosocial and medical needs of TNB youth.⁴³ Siblings felt challenged adjusting to the emergent and fluid nature of their TNB sibling’s identities, such as when different names/pronouns were used in different circumstances.^43–45 This difficulty was reported as particularly challenging when the sibling was the first to know of the TNB youth’s gender identity.⁴³ Siblings worried about accidentally disclosing their sibling’s TNB identity⁴⁵ and simultaneously felt isolated because they couldn’t talk about their feelings with others outside the family.⁴³ Siblings witnessed their TNB sibling had negative experiences based on their gender^43–46 and worried they might also be treated differently by people outside the family if they disclosed having a TNB sibling.⁴⁴ A few siblings reported they, themselves, were either specifically discriminated against or more generally treated differently for having a TNB sibling.⁴⁷

Despite these challenges, cisgender siblings perceived their relationship with their TNB sibling to be improved^43,45,46 and (eventually) saw it as their responsibility to support, respect, and/or protect their TNB sibling,^45,46 including acting as an intermediary with parents.⁴³ Overall, cisgender siblings thought having an TNB sibling was a generally positive experience and that their sibling’s gender journey resulted in both improved sibling relationships and family relationships.^43–45 Having a TNB sibling also increased awareness of and empathy for TNB populations more widely as well as other groups who experience marginalization in society.^45,46

Gaps in existing literature

Our review identified that most of the study samples were predominantly White. No identified studies evaluated both the TNB youth and their cisgender sibling’s perspective(s) concurrently. Additionally, none of the studies evaluated the age at which either the TNB youth disclosed their identity or the age that cisgender siblings learned of the TNB identity, nor whether age was associated with perceptions and/or experiences. None of the results included siblings who were primarily unsupportive at the time of the research. Notably, no interventions with or for siblings of TNB youth were identified, nor did any study specifically evaluate what tools or resources siblings of TNB youth might need. Though one manuscript reported data from Wave 1 of a longitudinal study,⁴¹ the rest used cross-sectional designs.

DISCUSSION

From our review, cisgender siblings are generally supportive of TNB youth with some requiring an initial period of adjustment, and this support may improve mental health outcomes among TNB youth. Sibling relationships tended to improve following disclosure. This improvement in relationships is consistent with the relationships between lesbian, gay, and bisexual (LGB) young youth and their heterosexual siblings, who may face similar challenges.²⁶ However, it is possible that sibling relationships are more likely to improve only when the pre-disclosure relationship was positive.⁴⁸

The data also support that social and medical transition of a TNB youth has a unique impact on siblings. Siblings who were included in their TNB sibling’s social gender transition, such as helping choose a name, seemed to adapt quickly to their sibling’s identity. Feeling connected to, and helpful in, the process of TNB youths’ receiving of GAMC may help siblings’ positive adjustment, as has been noted among siblings of youth with chronic health conditions.⁴⁹ Cisgender siblings shared their interest in further involvement and a need for knowledge for themselves to help them better support their TNB sibling. From our review, few siblings had an opportunity to participate in the TNB siblings’ medical appointments or other discussions with professionals regarding the receipt of GAMC. Given the familial context in which social and medical gender affirmation takes place, especially for TNB youth, a family-based approach to treatment could be an important addition to the current process.⁵⁰ For example, some siblings were aware of their TNB sibling’s gender identity before the parents were, which created unique challenges in keeping the identity from parents, which is also a concern among LGB youth.^25,26 Siblings also served as intermediaries in some cases, advocating for their TNB sibling inside and outside the family, which could have a specific emotional toll and potential relational strain when other family members are not accepting.^51,52

At present, we were unable to identify studies that investigated barriers and facilitators to sibling acceptance, adjustment needs after a sibling discloses as TNB identity, or interventions specific for siblings of TNB youth. Our findings suggest that an ideal intervention to support siblings of TNB youth could focus on 1) providing them education about what it means for an individual to have a TNB identity, 2) the gender affirming treatment processes and its associated risks, 3) opportunities to process their own feelings and experiences, and 4) guidance on navigating disclosure and others’ actual and perceived negative responses. Connection with other siblings may provide an opportunity for shared strategies to navigate unique situations, process their own feelings, and decrease feelings of isolation. Mutual support from other siblings could also help improve understanding of gender identity⁵³ and available resources,⁵⁴ increase their ability to demonstrate support, and mitigate stigma, as has been demonstrated among support groups for parents of TNB youth.^55,56 Guidance on how to advocate and/or defend their TNB sibling to others may also be beneficial.⁵⁷ Further, it is possible that receiving tangible social and emotional support could decrease the time it takes for cisgender siblings to fully adjust to, and accept, their sibling’s TNB identity.

Gaps in knowledge and Suggestions for Future Research

Studies either focused on TNB youths’ perspectives of their siblings’ acceptance or siblings’ experience with a TNB sibling; no studies included sibling pairs. Dyadic studies involving both index TNB youth and their sibling/s are needed to understand concordance around support and perspectives between TNB youth and their siblings. Similarly, several studies instructed the TNB youth to pick a single sibling on which to report perceived support, so it’s not known whether and to what extent the type and amount of support from various siblings could influence the mental health of TNB youth. It is also possible that one sibling’s support (or lack thereof) could influence other siblings’ responses. With the cisgender siblings in all the reviewed studies being biological siblings, future research is needed to understand how other types of siblings (e.g. step- and half-siblings and non-biological kin such as chosen family) may influence these associations.

Most studies focused on TNB youth’s mental health outcomes but corresponding studies investigating siblings’ mental health have not been identified. In this review, lack of formal support and resources was identified in all four qualitative studies.^43–46 Isolation, fear of discrimination and disclosure, and fear of TNB sibling’s safety were described among siblings in the samples.^43–46 The environmental stressor of having a TNB sibling may in some ways be similar to the stress experienced by siblings of someone with a chronic health condition, as there may be similarities in the need for medical appointments, changes to everyday routine in the household, and the draw on the family’s social and financial resources. As such, siblings of TNB youth may experience behavioral, social, and emotional changes and could be at increased risk for depression, anxiety, and impaired self-esteem.⁴⁹ At the same time, social support from peers, teachers, and healthcare providers can enhance coping abilities and support the development of empathy and compassion.⁴⁹

The majority of siblings in the included studies were older than their TNB sibling, which could be an impetus for the common theme of feeling the need to ‘protect’ their TNB sibling. Siblings of younger ages may have unique needs which could be explored in future work. More work is needed to understand barriers and facilitators to cisgender siblings’ acceptance, needs after disclosure, and how this varies across sibling ages and sibling types. For example, youths’ needs might vary based on the age at which the TNB youth’s gender identity is realized or the age at which the cisgender sibling learns of the gender identity. Prospective, longitudinal designs to describe the trajectory of sibling acceptance and support across time to identify potential intervention points are needed. Future work can investigate ways the adjustment period may be abbreviated to get back to baseline in already positive relationships or to facilitate improved relationships and support levels in more difficult relationships.

Study participants were predominantly White and non-Hispanic/Latiné, so the themes and results identified in the synthesized literature may not represent the experiences and needs of racially and ethnically diverse TNB youth or their siblings. Estimates of the size of the transgender community suggest there are differences by race and ethnicity, with a higher proportion of individuals from racial and ethnic minority communities identifying as transgender compared to White individuals.⁵⁸ Youth from racially and ethnically minoritized groups face additional stressors due to their multiple marginalized identities, which may have important consequences for mental health.⁵⁹ Family members of these youths may also have unique needs in understanding and coming to terms with a TNB identity. For example, results from a recent study of Black adults in the US showed they were less likely to know a transgender person and more likely than other respondents to say gender is based on assigned sex at birth.⁶⁰ Intersectional stigma may also play a role, with awareness of the compounded effects of racism and transphobia potentially influencing levels of family acceptance.¹⁶ Cultural, religious, and language factors may play a role in hindering or facilitating parental gender affirmation for some families as well.¹⁶ However, important strengths may be employed by families of color and in supporting and nurturing TNB children. A recent qualitative analysis of Black and Latine TNB youth revealed themes of parents affirming their “happy and thriving” child and reported that gender-affirming parenting behaviors improved their relationship with their child.¹⁶ Personal connection to the transgender community has been identified as an important predictor of support and acceptance, while rigid gender beliefs have been associated with less support.⁶¹ Thus, the needs of experiences of racially and ethnically diverse TNB youth and their siblings also need to be explored in future research. It is important to study families of color not only because these families may have unexplored challenges, but also because they likely also have unidentified strengths from which all families with TNB youth might benefit.

One limitation worth noting is the potential selection bias, particularly among samples recruited through gender clinics. Not all TNB youth desire GAMC and even those that due may face significant barriers related to parental support, insurance coverage, or the increasing number of state-level policies limiting access to care. Because of the need for parental consent to access GAMC, siblings included in some of the family-based studies may be more likely to be supportive than cisgender siblings in a family in which caregivers are unsupportive. Only one study indicated an attempt to recruit family members who may be unsupportive of their TNB sibling.⁴³ Recruiting siblings directly through nonparental sources could help to identify salient barriers to support among this population.

Conclusion

This review brings into focus the critical gap in this area and the unique needs of both TNB youth and their siblings. Given the increasing number of youths who report TNB identities at ages younger than 25, siblings may be a critical component in the positive developmental of TNB youth and a protective factor for mental health outcomes. More research is needed to explore the nuances and dynamics of sibling relationships between diverse TNB youth and their cisgender siblings over time. However, these findings highlight components that could serve as the initial foundation for the development of clinically meaningful work such as sibling-based support interventions to improve health outcomes for TNB youth.

ABBREVIATIONS:

TNB

transgender and nonbinary

GAMC

gender-affirming medical care

LGB

lesbian, gay, bisexual

LGBTQ

Lesbian, gay, bisexual, transgender and/or queer