1 Introduction

Gender dysphoria is a psychological condition characterized by a lack of alignment between the gender assigned to an individual at birth and the gender they identify with (APA 2013; Butler 2020). This leads to various levels of discomfort, as individuals may feel uncomfortable with their biological sex, primary and secondary sexual characteristics, and social gender roles. Over the years, the scientific debate to establish a clear definition of gender dysphoria and explore the social and psychological consequences for people who experience dysphoria has been varied and has covered different fields of interest (Lindley et al. 2022). This is due to several factors, such as the classification as a mental disorder, the diagnostic criteria used, the goals of therapeutic intervention, and its potential association with sexual orientation (Gonsalves 2020).

According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V), a diagnosis requires a condition persisting for over six months with a presence of at least two of these symptoms:

  1. 1.

    Discomfort regarding the alignment of perceived sex and primary and secondary sexual characteristics.

  2. 2.

    A desire to change one's sexual characteristics.

  3. 3.

    A wish to acquire the sexual characteristics of the opposite gender.

  4. 4.

    An inclination to identify as the opposite gender.

  5. 5.

    A longing to be acknowledged and treated as the opposite gender by others.

  6. 6.

    A belief in possessing emotions and reactions typical of the opposite gender.

Additionally, the second criterion states that the condition must be associated with clinically significant distress or impairment in social, occupational, affective-relational, and other areas of life (Frew et al. 2021). People who experience gender dysphoria may identify themselves as transgender, nonbinary, or, more generally trans + (Galupo et al. 2021), but not all trans and intersex people experience gender dysphoria. The increasing interest in gender dysphoria and its evolving diagnosis is evident in publications by scientific communities worldwide. These documents emphasize the necessity for comprehensive research assessments using advanced approaches and strategies for knowledge discovering.

Mapping scientific knowledge is the main task for understanding a topic by reviewing the literature, synthesizing research findings, and identifying future research areas. Bibliometrics simplify this process by providing a transparent and repeatable methodology based on statistical measurements of scientific production, scientists, and activities (Cuccurullo et al. 2016). They are widely used to assess field impact, researchers, papers, and journals, as well as to identify research gaps, trends, and opportunities.

In this study we employ a prominent approach to highlight both structural and cognitive patterns within the research field, namely science mapping (Aria et al. 2020). Science mapping allow to identify, visualize, and analyze the themes and trends in a research domain, both synchronically and diachronically, without repetition (Callon et al. 1983; Cobo et al. 2011). With this approach, we aimed to map the gender dysphoria research field, evaluate its scientific productivity, and highlight its current and emerging frontiers over the past 30 years. Our proposal is to provide insights into the field of gender dysphoria research. To achieve this, we present the following research questions:

RQ1: How has the landscape of scientific productivity in the field of gender dysphoria research evolved over time?

RQ2: What are the key trends and advancements reflected in the current state of the scientific literature?

RQ3: What are the significant events that have influenced the shifting trends and understanding of gender dysphoria over time?

The paper is structured as follows: Sect. 2 outlines the materials and methods utilized for collecting and analyzing bibliographic data. In Sect. 3, we present the main findings of the study. Section 4 is dedicated to discussing the results obtained, emphasizing their implications for research. In the last section, we provide conclusions considering both the limitations and advantages of bibliometric analysis.

2 Materials and methods

2.1 Research design

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA- Liberati et al. 2009) diagram was used to describe the entire process of data collection (Fig. 1). It provides a detailed representation of all the inclusion and exclusion criteria used for retrieving documents, ensuring the selection process is replicable and transparent.

Fig. 1
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PRISMA flow diagram

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The Web of Science (WoS) indexing database—launched by the Institute for Scientific Information (ISI) and now maintained by Clarivate Analytics—and Science Citation Index Expanded (SCI expanded) and the Social Science Citation Index (SSCI) Web of Science Core Collections were used to find the documents. WoS is widely considered as the bibliographic source offering the highest quality of information, with a coverage comparable to that of other well-known databases (D’Aniello et al. 2022). In order to identify publications related to gender dysphoria, gender identity disorder, and gender incongruence topics, the followed structured-query was used: ((TS = ("gender dysphoria") OR TS = ("gender identit* disorder*") OR TS = ("gender incongruenc*"))). The TS tag searches for query terms in titles, abstracts, and keywords fields of indexed documents. Quotation marks are used to identify records containing exact term sequences, while asterisks are wildcards used to find possible term variations (e.g., "gender incongruenc*" for gender incongruence or gender incongruences). Documents were collected in March 2023. We refine our search by selecting only articles, proceedings papers, review articles, and book chapters in english published from 1991 to 2022. The main bibliographic data including titles, abstracts, author names, and keywords, as well as cited references, were collected. The collection was screened by two selectors (AS and LDA) to include only relevant and coherent documents. We manually removed 184 documents from the collection due to the absence of abstracts or their overly specific focus on medical aspects, such as surgical procedures. At the end of the process, the final collection included 1847 documents. The bibliometrix R open-source package (Aria and Cuccurullo 2017) for quantitative research in scientometrics and bibliometrics was used to perform bibliometric analyses on the whole collection.

2.2 Reference publication year spectroscopy (RPYS)

Reference Publication Year Spectroscopy (RPYS) was introduced by Marx et al. in (2014) as a tool to detect the seminal documents of a research field. By considering the metadata from the references, including books, handbooks, or theses not necessarily indexed in a bibliographic database (Ciavolino et al. 2022), RPYS enables the identification of seminal documents as crucial historical roots of a field. The distinctive features of RPYS make it an invaluable tool to find the most influential documents, offering insights into the development of theories and their applications. RPYS analysis is represented by a plot with two lines: a black line representing the number of cited references per year; a red line measuring the deviation from the 5-year median at the current time t compared to the previous four (t-1, t-2, t-3, and t-4). Peaks of the red line in publication years identify which papers have the greatest influence in a publication set (Thor et al. 2018).

2.3 Conceptual structure: mapping the thematic evolution

The conceptual structure of a collection provides a comprehensive view of a research domain (Börner et al. 2003). It describes a research field or themes derived from documents or terms, sourced from authors' keywords, titles, or abstracts, and examined using co-word network analysis (Wang et al. 2019). Starting from these terms, knowledge of a document collection can be represented through a co-occurrence network. The frequency of two terms that co-occur is quantified and normalized by the association index (Eck and Waltman 2009). The result is a co-occurrence matrix presented as an undirected weighted network. Each node in the network corresponds to a term, with the size of a node typically proportional to the frequency of the associated term. The links between nodes and their strength measure the co-occurrence of terms. Once the analysis is employed, each cluster was then plotted on a two-dimensional graph call thematic map (Cobo et al. 2011) according to the Callon centrality, which quantifies the level of importance that a theme holds within a research field, and the Callon density, which serves as the degree of the theme’s development (Callon et al. 1983). The thematic diagram allows identifying four typologies of topics based on their position on the map. In the first quadrant (upper-right), topics characterized by both high centrality and density are known as well-developed motor themes. Moving to the second quadrant (upper-left), topics represent isolated or niche themes, exhibiting low centrality but high density, indicating limited significance for the research field. In the third quadrant (lower-left), there are topics known as emerging or declining themes, reflecting weak or marginal trends. Lastly, the fourth quadrant (lower-right) identifies basic and transversal themes cutting across various research areas.

In this study, we mapped the conceptual structure of the collected scientific documents to identify topics and trends in the research field of gender dysphoria. Dividing the reference timespan into distinct slices allows for tracking the evolution of research over time, providing a thematic map for each time slice. We performed a thematic evolution analysis by partitioning the reference timespan (1991–2022) into three time slices: (1) 1991–2012, to explore the primary themes investigated by the scientific community on gender identity disorder; (2) 2013–2017, to trace the scientific output after the release of DSM-V and the definition of gender dysphoria; (3) 2018–2022, to examine how the research has evolved since the introduction of International Classification Disease (ICD-11) and the shift to gender incongruence. Within each temporal interval, the Walktrap community detection algorithm (Pons and Latapy 2006) was performed using 200 authors’ keywords as unit of analysis. A minimum cluster frequency of 5 and an inclusion index weighted by word occurrences set to 0.1 were established. Each cluster in the maps was labeled with its top three most frequently keywords. In addition, to enhance the readability of findings, we reformulated some keywords by performing the followed text normalization process. We started by downloading all the author keywords used in the documents of the collection. Then, they were manually reviewing to identify any terms that needed to be remove if not informative for the study (e.g., clinical terms such as “patient” or “hospital”) or combined if they are synonyms.

3 Results

3.1 Data descriptions: main information about the collection

As reported in Table 1, the 1,847 documents included the collection were published by 5,498 authors on 585 different sources such as Journals and Books. The average citation per document is 28.98. The annual growth rate of the publication is 15.52%. As shown by the annual scientific production (Fig. 2), two events highlight an evident growth in scientific productivity. From 2013, the publications become more consistent (534–28.91%) until a rapid growth in 2018 (864–46.78%), according to the introduction of gender dysphoria as a psychological condition in DSM-V where an individual experiences a lack of alignment between gender identity and the sex assigned at birth. The World Health Organization (WHO) release the latest version of the ICD-11 in 2018 marking a notable moment in the research field, as it removes gender dysphoria from mental disorders and redefines it as gender incongruence. This change contributes to an increase in attention to the topic in terms of scientific productivity.

Table 1 Main Information about the collection
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Fig. 2
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The Trend of the annual scientific production from 1991 to 2022

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3.2 Identification of relevant documents

To measure the citations of scientific articles, two indicators were considered. Global citation (GC) is an impact measure of a document provided by Clarivate, counting the citations of a document received by all the records indexed on WoS. Instead, Local citation (LC) measures the number of citations received by records within a specific collection. These two indicators provide information on the global influence of a document across multiple subject areas (e.g., psychology, social sciences, medicine) and its impact in a particular field described by a collection of documents (i.e., gender dysphoria), respectively. The ratio between LC and GC provides a measure of the specificity of the documents being analyzed in the research field of gender dysphoria. This specificity is likely influenced by the database, which was collected based on the PRISMA diagram described in Sect. 2.1 Research Design.

Based on the GC index, the most cited document is “Endocrine treatment of transsexual persons: an Endocrine Society clinical practice guideline” (Hembree et al. 2009), followed by two other documents published by de Vries in 2014 and 2011. These papers are notable for developing clinical protocols. They highlight how the methodological developments are the primary references that incorporate puberty suppression, intersex hormones, and gender reassignment surgery to allow individuals to reassign their gender. The work by Wallien and Cohen-Kettenis (2008) also highlights the focus on pubertal treatment dysphoria and the psycho-social conditions of individuals. Furthermore, the most influential papers in terms of the LC/GC ratio (percentage) are Deogracias et al. (2007), Cohen-Kettenis (1997), and Cohen-Kettenis and Pfäfflin (2010). It is observed that the papers with a higher LC/GC ratio tend to approach dysphoria from a psychological perspective, while globally cited papers take a medical-treatment approach to dysphoria (Table 2).

Table 2 Most relevant documents
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To identify relevant documents considered seminal papers in scientific production, the Reference Publication Year Spectroscopy (RPYS) was used. Figure 3 displays two lines representing the Number of Cited References (NCRs) per year and the deviation from the 5-year median, while Table 3 lists the seminal documents that identify the historical scientific roots of gender dysphoria. The table includes the publication year, document identification, and a summary of the main theme. Documents published from 1948 to 1968 focused on the origin and development of sexuality, particularly in male subjects, and the psychological conditions that lead them to perceive themselves as the opposite gender. Later, Green’s studies (1974; 1987) established the groundwork for the definition of gender identity disorder, treating the disorder from a medicalized perspective as well, through the definition of several criteria for the diagnosis (Zucker and Bradley 1990). Since the 2000 s, studies have emphasized the treatment of gender dysphoria through hormone therapies and surgery treatments (Hembree et al. 2009; Murad 2010). Additionally, attention has been given to the psycho-social difficulties experienced by individuals who experience dysphoria (Coleman 2012; Dhejene 2016).

Fig. 3
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Reference publication year spectroscopy

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Table 3 Seminal documents
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3.3 Authors’ scientific production

The top 10 authors (i.e., the most productive in terms of the number of published articles) are listed in Fig. 4, highlighting their scientific production over time. Three main information are summarized in this plot for each author: (1) the scientific timeline, which measures their research activities, traced by the red line; (2) the number of published articles indicated by the bubble size; and (3) the number of total citations per year proportional by the color intensity of bubble. In our collection, Zucker KJ and Bradley SJ had the most extended scientific timeline production (1992—2022), followed by Cohen-Ketten PT, which published more articles in 2016 than others and received almost 120 total citations. She is a Professor Emeritus of gender development and psychopathology at the Department of Child and Adolescent Psychiatry, University Medical Center Utrecht, leading the Group on Gender Identity Disorders (DIG), the only national reference center in the Netherlands for gender identity disorders. In addition, Cohen-Ketten PT is internationally recognized as one of the experts in transsexualism and holds membership in various scientific committees of the Harry Benjamin International Gender Dysphoria Association, a non-profit organization focused to advance evidence-based care, education, research, public policy, and respect in transgender health. Zucker KJ, instead, is a professor at the Department of Psychiatry and Psychology at the University of Toronto and editor-in-chief of Archives of Sexual Behavior since 2001. He published significant contributions about gender dysphoria, albeit with controversial implications for sex and gender minorities. Throughout his extensive career, Zucker has formulated disease models aimed at understanding the experiences of these minority population. Currently, he is Head of the Child and Adolescent Gender Identity Clinic and Psychologist-in-Charge at the Child and Family Studies Centre, Clarke Institute of Psychiatry (Toronto). He, also, collaborated with Bradley SJ, Professor Emeritus at the Department of Psychiatry at the University of Toronto, a fellow of the Royal College of Physicians, and chair of the DSM-IV Subcommittee on Gender Disorders, collecting clinical and research data over twenty years and became an international authority on gender dysphoria in children and adolescents. She has also contributed to the development of a specific therapeutic approach aimed at mitigating the progression of gender diverse youth towards transgender adulthood, commonly referred to as reparative therapy.

Fig. 4
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Top authors’ production over time

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3.4 Country scientific collaboration and production

Countries' productivity and international collaboration were measured using the Single Country Production (SCP) and Multiple Country Production (MCP) indexes. SCP refers to articles with authors from one country, while MCP includes articles with co-authors from different countries. By dividing the MCP value by the total number of articles, the MCP Ratio is obtained, which measures the percentage of articles written by a country with at least one author from another country.

As reported in Table 4, among the top ten productive countries, Netherlands (MCP Ratio = 34.6%), Belgium (MCP Ratio = 40.4%), and Sweden (MCP Ratio = 30.4%) are the most open to international collaborations, while highly productive countries such as the USA, United Kingdom, Canada, and Australia have a lower propensity to international collaboration (MCP Ratio = 9.17%, 20.00%, 25.8%, and 19.10%, respectively). As highlighted from the country collaboration map (Fig. 5), the USA is the leading country in terms of publications and was mostly shared with Canada and Australia. In summary, European nations tend to collaborate more strongly, with the Netherlands and Norway especially having a dense network of collaborations. It is worth noting that the Netherlands, Belgium, and Sweden have been recognized for their progressive and inclusive policies regarding gender identity and transgender rights. These countries have implemented laws and regulations that support transgender individuals, such as allowing legal gender recognition and providing access to healthcare services related to gender dysphoria. In particular, Netherlands is known for its long history of research and expertise in the field of gender identity and transgender healthcare. It has recognized as one of the European countries for their progressive and inclusive policies regarding gender identity and transgender rights, introducing laws and regulations that support transgender individuals, such as legal gender recognition and providing access to healthcare services related to gender dysphoria. In addition, this country provides specialized gender clinics and centers of excellence, such as the VU University Medical Center in Amsterdam, which have contributed significantly to the research and treatment of gender dysphoria. In recent years, the United States has experienced a significant increase in awareness and recognition of gender dysphoria and transgender rights. This has led to more acceptance and support from society for researching gender dysphoria. The growing visibility and better understanding of transgender individuals' experiences have likely sparked interest in studying and addressing the challenges they face. Additionally, having access to research funding is crucial for scientific productivity in any field, including gender dysphoria. The United States has various funding agencies, like the National Institutes of Health (NIH), that provide substantial financial support for medical and psychological research. These funding opportunities encourage researchers to study gender dysphoria and contribute to the overall progress of scientific knowledge.

Table 4 Country production
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Fig. 5
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Words DYNAMICS OCCURRENCES OVER TIME

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3.5 Topic analysis: words frequency over time

In the DSM-IV (APA 1994), the diagnosis of gender dyspjotia was classified as "Sexual and Gender Identity Disorders”, which referred to as gender identity disorder. Originally, the gender identity disorder described persistent identification with the opposite sex and discomfort with one's assigned gender role (Bradley and Zucker 1997). The focus was on the emotional distress caused by this incongruence rather than the individual's gender identity (Carroll 2007). Figure 5 shows the terminology evolution used to describe gender dysphoria from 1991 to 2022. The graph indicates the cumulative frequency of the following terms: gender dysphoria, gender identity disorder, and gender incongruence. Gender identity disorder was widely used in scientific literature until 2015, despite the use of gender dysphoria in earlier works. In 2013, there was a notable shift in the terminology used for gender dysphoria, following the change in the DSM-V to remove the term disorder and reduce the associated stigma. Gender dysphoria was redefined as a psychological condition characterized by an incongruity between one's gender identity and the sex assigned at birth. Then, the use of the term gender dysphoria increased significantly, surpassing that of gender identity disorder. Since 2018, the WHO has replaced gender dysphoria with gender incongruence to reduce the pathologization of gender dysphoria. Although the graph indicates an increase in the use of the term gender incongruence since 2018, gender dysphoria remains the most widely used term.

3.6 Conceptual structure: thematic evolution findings

3.6.1 Thematic map of 1991–2012 time slice

Findings of the first thematic map (1991–2012) are showed in Fig. 6. The motor themes highlight the scientific community's interest in psychological and psychic issues related to individuals experiencing dysphoria. In particular, the light red cluster focuses on psychiatric disorders, such as psychosis and schizophrenia, and their impact on body perception. The light green cluster summarizes themes related to twin studies examining genetic and environmental influences on physical and behavioral traits, while the green cluster refers to the spectrum of sexual development disorders, specifically gender dysphoria diagnoses in intersex individuals. The basic themes include different clusters related to defining criteria for the diagnosis of gender identity disorder and dysphoria, with a focus on transgender and transsexual subjects (Cohen-Kettenis et al. 1997). During this period, topics on sex steroids, such as estrogens and testosterone, were investigated. Paraphilias, including hebephilia, themes were also discussed. Kinship ties were considered concerning sexual orientation, particularly in men, founding a significant correlation between male sexual orientation and fraternal birth order. This indicates that the older brothers a male has from the same mother, the more likely he is to have a homosexual orientation. Moreover, prevalent research focused on body perception in individuals with gender dysphoria and its relationship with the onset of anorexia nervosa. Three clusters were identified as emerging or declining themes. The light green cluster pertains to primordial studies on same-sex physical attraction for both men and women. The light red cluster realted to eating disorders appears to be fundamental in individuals experiencing dysphoria, as well as early research testing the correlation between autism and gender identity disorders. Finally, clusters identified as niche themes, are related to psychological conditions topics that dysphoric people experiences, such as anxiety and depression or the onset of personality disorders, but also to paraphilias related to masochism and transvestism.

Fig. 6
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Thematic map 1991–2012 time slice

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3.6.2 Thematic map of 2013–2017 time slice

Figure 7 shows the thematic map for the period of 2013–2017. Based on the motor themes, the light grey cluster pertains to research on sexual identity and the LGBTQ + community, while the azure cluster focuses on the two major classification systems used in psychiatry (i.e., DSM-5 and ICD-11). The yellow cluster covers literature on kinship, sexual orientation, and sibling relations. These themes are being extensively developed over time. The basic themes, including gender-affirming surgery, gender dysphoria, gender, and transgender, are central to the scientific literature. Mental health aspects such as anxiety, depression, hormone studies, and paraphilias are also widely explored. The niche themes include different clusters that refer to studies on sexuality and sexual desire, as well as the redefinition of how gender roles are socially structured (Davis et al. 2016). Additionally, there are clusters related to the medical field, exploring the topic of castration, and numerous contributions that analyze visual-spatial abilities based on sex differences and gender identity. Among the emerging or declining themes, there is a growing interest in verifying whether individuals experiencing dysphoria abuse harmful substances such as alcohol and drugs, as well as analyzing risky sexual behavior.

Fig. 7
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Thematic map 2013–2017 time slice

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3.6.3 Thematic map of 2018–2022 time slice

Based on the thematic map of the period 2018–2022 (Fig. 8), the green cluster concerning access to health services for transgender people, emphasizing the challenges faced by transgender people in accessing medical care, was identified as motor theme. The basic themes in this timespan include gender dysphoria studies and gender affirmation operations. Two clusters are identified as emerging or declining themes. The light azure cluster pertains to the medical, economic, and social challenges that FtM individuals face when carrying a pregnancy, while the purple cluster specializes in surgical treatment therapies for individuals experiencing dysphoria, alongside hormone treatments including testosterone and other hormone variants. Regarding emerging or declining themes, topics related to eating disorder and body image, which refers to the way individuals experience their bodies on a psychological level, are identified. Body image is shaped by numerous factors and profoundly impacts individuals' perceptions and interactions within their environment. Disruptions in body image are commonly observed in both eating disorders and gender dysphoria, highlighting the intricate relationship between psychological well-being and self-perception. In the niche themes, there is a growing interest in innovative techniques for gender affirmation surgery and a debate on the implications of fertility and sperm preservation on personal health treatment.

Fig. 8
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Thematic map 2018–2022 time slice

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4 Discussion

This study provides valuable insights into the current understanding and advancements in the field of gender dysphoria. By examining a wide range of scholarly works and research studies, a comprehensive landscape emerges regarding the complexities of this phenomenon. The findings underscore the substantial influence of gender dysphoria research on reshaping our comprehension of gender identity. The research delves into the psychological, social, and medical aspects of gender dysphoria, exploring factors like self-acceptance, social support, mental health outcomes, and the effectiveness of different interventions and treatments. Scholars and researchers have engaged in extensive debates regarding gender dysphoria since the 1970 s, leading to a transformative shift in understanding the condition. Initially categorized as a gender identity disorder in DSM-III (APA 1994), the term emphasized a pathologizing and identity-focused perspective. There has been a significant increase in scientific productivity related to dysphoria, with an evident surge since 2013.

By analyzing the annual growth rate of publications, two distinct periods of increased scientific productivity can be observed. Prior to 2012, the research field was characterized by a relatively constant annual publication trend with a lower number of documents. However, a shift of scientific productions occurred from 2013, marked by a significant advancement in the research domain, with the incorporation of the term gender dysphoria in the DSM-V. The inclusion of this term reflected a milestone in the field and has contributed to the heightened scholarly output. This revision signifies a fundamental shift in conceptualizing the condition, emphasizing the individual's experience of distress and removing the potentially stigmatizing connotation associated with the term disorder (Sennott 2010). By focusing on the distress arising from the incongruence between an individual's lived or expressed gender and their gender assigned at birth, the DSM-V adopted a more person-centered perspective. It acknowledges the distressing nature of the situation while refraining from labelling the individual's entire gender identity as a disorder. Moreover, this change highlights progress in the understanding of gender and transgender experiences (Miscioscia et al. 2020), fostering greater social acceptance and promoting appropriate treatment for those experience gender dysphoria. Notably, the new version of the diagnostic manual has allocated a separate chapter for gender dysphoria, distinct from paraphiliac disorders and sexual dysfunctions, further facilitating focused assessment and interventions in this area. However, some contradictions emerge in the new approach. It is unclear how gender dysphoria is fully connected to distress when the latter is not always present and the diagnosis encompassed intersex individuals similarly to transgender individuals, but there is a lack of clarification on how symptomatic indicators can capture the experience of intersex individuals (Davy and Toze 2018). Additionally, the updated version acknowledged identities beyond the binary, marking a significant change in perspective (De Cuypere et al. 2010). If the DSM-V undoubtedly played a role in formal depathologization for individuals experiencing their gender identity differently from their assigned sex at birth, it was the decision by the WHO that is considered a true breakthrough (Dakic 2022). Removing gender dysphoria from the classification of mental disorders changed the designation to gender incongruence. With the recent change, individuals are no longer required to demonstrate severe discomfort or significant impairment in their ability to function effectively at work or in social situations. This means that people who feel uncomfortable with their assigned gender at birth, even if it's not severe, can now qualify for treatment in many countries. While this may improve accessibility to health care for transgender people seeking treatment, it also raises concerns about the potential pathologisation of individuals who do not experience discomfort in relation to their gender incongruence and may not seek treatment at all (Drescher et al. 2012).These changes in diagnostic criteria and the reclassification of gender dysphoria as gender incongruence not only reflect evolving understandings of gender identity but also drew increased attention to the topic within the scientific community (RQ1).

Recognizing the evolution of focus and related issues surrounding gender dysphoria is crucial for ongoing progress in the field and providing support to individuals experiencing this condition. Over time, there has been a significant shift in the understanding and approach to addressing gender dysphoria, reflecting an increasing awareness of gender identity. The first thematic map (1991–2012) indicates that scientific research primarily focused on the origin of physical and sexual attraction between individuals of the same sex, aiming to comprehend the genetic and environmental factors influencing sexual orientation, as demonstrated by the study conducted by Fridell et al. (1996). This research played a pivotal role in dispelling myths about sexual orientation, affirming that it is not a choice and is not influenced by psychological or social factors. These studies provided a foundation for further exploration of sexual development disorders (Furtado et al. 2012), such as sexual dysfunction, paraphilias, and gender identity disorders (Blanchard 1993; Freund and Watson 1993; Brad Ford 2001; Abdo et al. 2001), which are classified in the DSM-IV. These studies highlighted the intricate nature of gender dysphoria, emphasizing its biological basis and establishing the groundwork for evaluating the efficacy of gender-affirming treatments in enhancing the quality of life for individuals with gender dysphoria. Blanchard (1993) conducted a longitudinal study on a group of transgender men, revealing that gender dysphoria often manifests in childhood and tends to persist over time. In a complementary study, Abdo et al. (2001) explored gender dysphoria in children, establishing a greater likelihood of gender dysphoria in those who have a sibling experiencing the same condition.

Throughout this period, significant medical research was conducted on transvestism (Docter and Prince 1997) and transsexualism. Studies initially centered on children diagnosed with gender identity disorders (Linday 1994; Zucker et al. 1999), as well as the utilization of steroid-based hormone therapy to facilitate the development of physical characteristics aligned with one's gender identity (Meyer-Bahlburg 2013). Additionally, scientific production during this time delved into the treatment of self-image and body image concerning individuals' experiences of their gender identity and the subsequent clinical and psychological implications that may arise (Kraemer et al. 2007). Research also focused on anorexia nervosa (Winston et al. 2004) and eating disorders (Vocks et al. 2009) to comprehend the impact of gender identity disorder on self-perception and body image.

With the publication of DSM-V in 2013, a significant turning point occurs in the scientific literature on gender dysphoria, replacing outdated categories such as transvestism and gender identity disorder. This period also highlighted a growing interest on social challenges experienced by individuals with gender dysphoria. Several studies investigated the psychological conditions related to psychosocial support (Reisner et al. 2015; Brown and Jones 2016; Durwood et al. 2017), risky sexual behavior (Cerwenka et al. 2014), and substance abuse, such as drugs and alcohol (Coleman et al. 2012; Drescher and Byne 2012), particularly among adolescents (Davey et al. 2014; Zucker et al. 2013). The psychosocial support is an important factor in protecting the mental health and well-being of transgender youth and highlight the importance of addressing social stigma to reduce the risk of substance abuse among transgender individuals.

The theme of access to health treatment and medical services for individuals with gender dysphoria, along with the social and health barriers that hinder such access, emerged prominently during the period from 2013 to 2017. The scientific literature demonstrated a shift towards a deeper understanding of the challenges faced by individuals with gender dysphoria, with a particular focus on providing support and access to appropriate health services (Dhejne et al. 2016). Overall, a growing recognition of the social challenges experienced by individuals with gender dysphoria, beyond just the medical aspects of the condition, was examined. The studies highlighted the need for greater support and access to appropriate health services for this population, emphasizing the psychosocial factors that may affect their well-being (Lindley et al. 2021). From 2018 to 2022, the literature on gender dysphoria has seen a notable shift towards ethical and medical considerations aimed at upholding patient dignity. Specific medical advancements, such as phalloplasty and vaginoplasty, have been developed to address the needs of transgender individuals, with a focus on understanding the implications of hormonal treatments on reproductive choices. Papadopulos et al. (2021) underscored the significant role of gender affirming surgery in providing comprehensive care for transgender individuals. Their research emphasizes that such surgical interventions not only enhance various aspects of daily life but also positively impact mental well-being and self-esteem. Additionally, there has been increasing attention to the possibility of transgender individuals becoming pregnant. Grin et al. (2021) examines the potential for transgender individuals to conceive after undergoing gender-affirming hormone therapy (GAHT), suggesting that those who have preserved sperm before beginning therapy may still have the ability to become pregnant. An attention was also directed towards primary care and medical assistance for transgender patients, promptly and effectively addressing their specific healthcare needs (Lindley and Galupo 2020; Sood et al. 2021) (RQ2).

Over the past two decades, shifts in trends and perceptions regarding gender dysphoria have been influenced by a multitude of events such as the LGBTQ + rights movements, the evolution of gender theories, and diagnostic revisions. One significant change in diagnosis involves a shift from a behavioral and sexual focus to a broader consideration of a person's identity. These developments led to a change in language and perception, emphasizing the importance of self-identification and aiming to reduce stigmatization and discrimination of transgender people (Crapanzano et al. 2021). In 2018, the WHO removed transgender identities from mental disorders, introducing the diagnosis of gender incongruence. The new criteria for this diagnosis include the presence of a desire to transition, which involves seeking gender-confirming treatments such as hormone therapy or surgery.

This shift reflects the recognition that being transgender is not a mental disorder, with significant implications: reparative therapies, forced hospitalization, and sterilization, once aimed at altering or suppressing an individual's gender identity, are now acknowledged as harmful and are no longer endorsed by the WHO. Overall, these variations mark a significant step forward in recognizing and respecting transgender individuals, promoting the rights, and rejecting harmful approaches that deny the gender identities. Furthermore, there is the potential for convenient access to healthcare services, ensuring that these individuals receive assistance from qualified and well-trained healthcare professionals. By removing transgender identities as mental disorders and adopting a more inclusive and affirming approach, the WHO aims to promote respect, dignity, and equal rights for individuals whose gender identity differs from their assigned sex at birth (RQ3).

5 Conclusion

In this study, we aim to make a meaningful contribution to gender dysphoria research by employing various science mapping approaches, providing a comprehensive overview of the evolving scientific production over time. Despite outlining the evolution of gender dysphoria topics, this study present some limitations.

Firstly, the inclusion of articles exclusively from WoS does not allow for an understanding of the entire literature on the selected topic. The integration of metadata from different databases poses challenges due to inherent disparities in data formats and structures across platforms. It's important to note that databases such as Scopus or PubMed also have their respective strengths and weaknesses (Falagas et al. 2008). Numerous articles may have been published in journals not yet indexed, eluding detection by any database. Given these constraints, the publications analyzed in our study may not precisely represent global research activity on dysphoria studies. However, these data offer valuable insights into trends, especially concerning the approach employed to analyse the evolution of interest in the topic before and after specific events (Aria et al. 2022).

Transitioning to ethical considerations, we acknowledge the unique challenges associated with researching gender dysphoria—a subject deeply entwined with personal identity, social stigma, and mental health. Our approach is rooted in sensitivity and respect for the experiences of individuals with gender dysphoria. We are keenly aware of the potential for research findings to be misinterpreted or misused, posing harm to transgender and gender-diverse communities. To mitigate this risk, we carefully frame our findings within the context of promoting understanding, inclusivity, and the importance of evidence-based care and support for individuals with gender dysphoria. Our ethical approach to researching gender dysphoria is grounded in a commitment to do no harm, advance knowledge with compassion and respect, and contribute to a more inclusive and supportive society for all individuals, irrespective of their gender identity.

In conclusion, our work sets the base for future research efforts aiming to delve deeper into the phenomenon using other statistical approaches. This would provide a wider understanding of the topic and encourage collaboration with experts and scholars, offering valuable insights and assessments of key concepts and methods.