Mapping current research on biomarkers associated with the diagnosis of pedophilia: a scoping review

Background: Pedophilia remains a challenging area of study due to its sensitive nature and the ethical considerations surrounding research involving individuals with deviant sexual interests.

Objective: The aim of this review was to systematically explore and present the current research status on biomarkers in pedophilia. The focus was on biomarkers that may support the diagnostic process, treatment evaluation and assessment of risk and recidivism of pedophilia.

Methods: Based on literature searches [MEDLINE, EMBASE, Scopus, APA PsycNet, Google Scholar], a scoping review was applied between January and March 2024, including studies in adults diagnosed with pedophilia, published within the last decade.

Results: A total of 39 studies were included in the study sample. These encompassed only male participants. Biomarkers associated with pedophilia were identified and categorized as following: genetic/epigenetic and neuroendocrinal, physiological, cognitive/behavioral, and neuroimaging/neurofunctional. Results indicated the presence of cognitive deficits or impairments, especially in memory and executive functions, significant structural and functional brain differences in neuroimaging, with evidence of altered connectivity, volume reductions, and abnormal brain activation patterns. Physiological biomarkers revealed altered physical traits, attentional control, and sexual arousal patterns in pedophilia, with neural responses suggesting dysfunction in prefrontal cortex and error processing areas. Lastly, genetic and neuroendocrine studies suggested a potential link between epigenetic alterations in the serotonergic and testosterone systems, with lower testosterone levels and signs of prenatal androgen exposure observed in pedophilic individuals.

Conclusions: This review mapped the existing state of the art data in biomarkers in pedophilia, also supporting the existence of promising biological systems implicated in the pathophysiology of pedophilia, thus emphasized the need for further research in the field.

Systematic review registration: https://osf.io/8v9wn, identifier https://doi.org/10.17605/OSF.IO/8V9WN.

Introduction

Pedophilia is a psychiatric disorder characterized by a primary or exclusive sexual attraction to prepubescent children (1). It is important to distinguish that not all individuals who commit child sexual offenses have pedophilia, and conversely, not all individuals with pedophilia engage in sexual offenses. Pedophilia refers specifically to a sexual preference, whereas child sexual offending involves actual criminal acts against children, irrespective of the perpetrator’s sexual orientation; in contrast, sexual arousal toward children is a prerequisite for the diagnosis of pedophilia (1).

According to the International Classification of Diseases, 11^th Revision (ICD-11) (1), pedophilic disorder is “characterized by a sustained, focused, and intense pattern of sexual arousal—as manifested by persistent sexual thoughts, fantasies, urges, or behaviors—involving pre-pubertal children”. Additionally, the person must either act on their sexual preference or suffer distress due to their deviant sexual preference (1). Similarly, the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) defines pedophilic disorder as “recurrent, intense sexually arousing fantasies, sexual urges, or behaviors involving sexual activity with prepubescent children” persisting for at least 6 months, also causing marked distress or interpersonal difficulties (2).

In psychiatry, where diagnoses are based primarily on behavioral descriptions (e.g., those outlined in the DSM or ICD), developing objective biomarkers presents significant complexities (1–5). Nevertheless, pedophilia remains a challenging subject to study due to its ethical sensitivity and the difficulties surrounding research in individuals with deviant sexual interests. Factors such as stigma, legal risks, and institutional barriers often limit access to participants and constrain study designs, all resulting in samples that are predominantly drawn from forensic or incarcerated populations (3). This can introduce bias and limit the generalizability of findings across the broader spectrum of individuals with pedophilic interests (1–3).

Understanding the neurobiological underpinnings of pedophilia and identifying reliable biomarkers is essential for improving diagnostic accuracy, guiding treatment, and assessing risk and recidivism (3, 4).

Data from systematic reviews and meta-analyses examining the psychological, emotional, and social impact of pedophilic assault on survivors and their families help contextualize the broader consequences of pedophilic behavior (6, 7). These findings not only underscore the public health relevance of the issue but also highlight the critical need for accurate diagnosis and early identification, areas where biomarker research may offer valuable tools. To further illustrate the scope of this impact, child sexual abuse, often perpetrated by individuals with pedophilic disorder, has profound and long-lasting effects on survivors and their family systems. An umbrella review by Hailes et al. (2019), found significant associations between childhood sexual abuse and a wide range of psychiatric, psychosocial, and physical health outcomes (6). The strongest associations were identified for conversion disorder, borderline personality disorder, anxiety, and depression. Beyond the individual survivor, empirical evidence also demonstrates the substantial emotional toll experienced by non-offending family members. The study by Fong et al. (2020) revealed that caregivers experienced significant emotional and psychological distress, including anger, depressive symptoms, and guilt (7). Sources of distress included concerns about their child’s well-being, negative self-perceptions regarding their parenting, family members’ reactions, and even resurfacing memories of their own past maltreatment. These findings emphasize the enduring impact of such abuse and reinforce the importance of early detection strategies, including biomarker research, to prevent or mitigate long term harm.

Biomarkers are defined as “a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes or pharmacological responses to a therapeutic intervention” (5, 8). Research has proposed a range of potential biomarkers for pedophilia, including neuroimaging, neurochemical indicators and physiological assessment, including penile plethysmography and eye tracking (3, 4, 9–11). Some studies have even explored genetic markers (4). However, many of these findings stem from small, cross-sectional studies, and replication remains limited (3, 4, 9–11). Furthermore, several proposed biomarkers lack specificity and may overlap with other psychiatric or developmental conditions, which complicates their interpretation in clinical contexts (1, 2).

It is also important to recognize that biomarkers are not intended to replace clinical judgment or comprehensive assessments. Rather, they should be viewed as potential supplements to existing diagnostic and risk-evaluation tools, contributing to a multi-modal understanding of the condition. Lastly, cultural context, societal stigma, and the highly sensitive nature of pedophilia continue to shape both the availability of research data and the ethical boundaries within which such studies must operate. Yet, conducting systematic reviews that synthesize existing evidence is crucial in identifying gaps, refining methodologies, and establishing a more comprehensive understanding of pedophilia biomarkers.

Thus, the aim of this scoping review was to explore and map the current research state of research on biomarkers for pedophilia. The focus was on biomarkers that may support diagnostic processes, treatment monitoring and assessment of risk and recidivism in individuals diagnosed with pedophilia.

Methods

Research questions

Based on the aim of the present scoping review, the following research questions framed the inclusion criteria, search strategy, and synthesis:

1. What types of biological markers have been investigated in relation to the diagnosis or understanding of pedophilia?

2. What methodological approaches have been used to study biomarkers in individuals with pedophilic disorders? What are the main limitations, challenges, and ethical considerations reported in the literature regarding biomarker research in pedophilia?

3. What are the reported structural, functional, genetic, cognitive, and physiological differences associated with pedophilia in the existing literature?

4. How do biomarkers differ between pedophilic individuals who have offended and those who have not?

Protocol and registration

This scoping review followed the methodological framework proposed by current guidelines for conducting scoping reviews (12). Reporting adhered to the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR)² checklist (please see Table S1 in Supplementary material. The protocol was registered on Open Science Framework-OSF (https://osf.io/8v9wn).

Eligibility criteria

Eligible studies were empirical, peer-reviewed publications, focused on adults diagnosed with pedophilia, including both offenders and non-offenders, irrespective of: (a) the setting or context in which diagnosis was established, (b) patient background characteristics (e.g., age, treatment status, comorbidities), and (c) diagnostic and reporting method used (e.g., clinical interviews, metric tools: questionnaires/scales, physical examination, or self-report).

Comparative studies evaluating interventions or diagnostic tools/procedures in the target population were also included.

Systematic reviews, meta-analyses, narrative reviews, case reports and case series, empirical studies with fewer than 10 participants, and conference abstracts, were excluded. Empirical studies exclusively including non-pedophilic sexual offenders and records in non-English were both excluded. Restrictions were applied regarding the year of publication to exclusively include state-of-the art research on biomarkers, e.g., published work in the last decade.

Information sources

A comprehensive literature search was conducted from January to March 2024 by two experienced health researchers. The search strategy was developed in consultation with a medical librarian to optimize the rigor of the process. The databases searched included: MEDLINE via OVID, EMBASE via OVID; PsycINFO; Scopus via Elsevier.

Search strategy

A combination of controlled vocabulary (MeSH terms) and free-text key-words vocabulary was employed. The MEDLINE strategy included terms as follows: ((‘child sexual abuse’[MeSH Terms] OR pedophilia[MeSH Terms] OR paedophilia[MeSH Terms]) AND (biology[Title/Abstract] OR biological[Title/Abstract] OR genetic[Title/Abstract] OR epigenetic[Title/Abstract] OR imaging[Title/Abstract] OR biomarkers[Title/Abstract] OR hormones[Title/Abstract] OR EEG[Title/Abstract] OR neuropsychological[Title/Abstract] OR neurotransmitters[Title/Abstract] OR ‘penile plethysmography’[Title/Abstract] OR ‘eye tracking’[Title/Abstract] OR etiology[Title/Abstract]).

Additional search methods included backward citations tracking and forward citation searching of relevant reviews and included articles.

Selection of sources of evidence

Covidence tool (13) for data management, automatic duplicate removal and independent screening of relevant studies was used to export search outcomes. Two members of the research team (AC, AE) independently screened abstracts and titles of search outcomes for relevance. In cases that the relevance of a study was unclear according to the title or the abstract, the full text was reviewed. Any discrepancies were resolved through discussion or by consultation with a third researcher (MK).

Data charting process

All search outcomes deemed as relevant were independently reviewed by the three researchers (MK, AE, AC) to confirm eligibility. This was achieved by fully assessing the scope of data responding to the objectives of the present review. Inter-rater reliability was monitored and documented at this point, by the degree of agreement between the three researchers, regarding the inclusion or not of all search outcomes deemed as relevant. A custom data assessment tool (“include”/”exclude with documentation comments”) was developed and pilot tested on six initial studies.

Data extraction was guided by a standardized form created by AC and tested by AE. Data elements and extraction methods were mutually agreed upon by all members of the research team. Extracted data included: first author, country of study, year of publication, study design and setting, sample characteristics (sampling method, sex, size, age), diagnostic methods and inclusion criteria, primary result on biomarkers, biomarker type/category, and testing paradigm/methods.

Critical appraisal of individual sources of evidence

The search outcomes which were confirmed as relevant underwent methodological quality assessment using the Joanna Briggs Institute critical appraisal tools (14). Three researchers (MK, AE, AC) independently conducted the appraisal, and discrepancies were resolved according to the degree to which the researchers identified supporting data in the manuscript for those items identified as controversial. An assessment form was created to document assessment judgments. These data are presented in Table S2, S3 in Supplementary material. Although methodological quality was appraised, no studies were excluded based on quality to preserve the breadth of data, consistent with scoping review methodology. Specifically, the aim of a scoping review is to present the spectrum of existing data on a topic, along with the quality of this data instead of focusing on the relationship among variables and relevant effect size (15).

Synthesis of results

The synthesis of data involved narrative aggregation and mapping of identified biomarkers across studies. Key patterns, trends, and methodological limitations were summarized to capture the current state of evidence and to highlight gaps. This synthesis provided insight into the diversity and limitations of the evidence base and suggested directions for further biomarker research in pedophilia.

Results

Selection of sources of evidence

A total of 320 studies were identified through four databases: EMBASE (n=147), Medline (n=168), PsycINFO (n=3), and Scopus (n= 2). After the removal of duplicates, 313 titles and abstracts were screened. Of these, 238 were excluded, 75 were sought for retrieval and 73 were reviewed in full for eligibility (two studies could not be accessed in full text). An additional 43 studies were excluded based on eligibility criteria. Nine additional studies were identified through hand-searching, resulting in 39 studies included in the review (please see Figure 1).

Figure 1

Figure 1. Prisma flow chart of the identification and inclusion/exclusion process.

Characteristics of sources of evidence

Details of the 39 included studies, such as author, year of publication, country of origin, research aim/objectives, sample characteristics, methodology, are presented in Tables 1–4. All studies were published between 2013 and 2023 in English. Most were conducted in Germany (n=23), followed by Canada (n=5), and the U.S.A (n=3). Twelve studies recruited participants from the “Neural Mechanisms Underlying Pedophilia and Sexual Offending Against Children” (NeMUP) research project. The majority were case-control studies (n=37), with two cross-sectional studies (n=2). Samples typically required participants to be aged 18 years or older, and diagnosed with pedophilia, including both offending and non-offending exclusively male individuals.

Table 1

Table 1. Study characteristics and main findings on neuroimaging/neurofunctional biomarkers.

Table 2

Table 2. Study characteristics and main findings on genetic/epigenetic and biochemical biomarkers.

Table 3

Table 3. Study characteristics and main findings on physiological biomarkers.

Table 4

Table 4. Study characteristics and main findings on cognitive/behavioral biomarkers.

Critical appraisal of evidence

In accordance with scoping review methodology, no studies were excluded based on quality appraisal outcomes. Appraisal was conducted for both case-control and cross-sectional studies (please see Tables S2, S3 in Supplementary material).

Results of individual sources of evidence

Biomarkers associated with pedophilia were categorized into four domains: (1) genetic/epigenetic and neuroendocrinal (n=5), (2) physiological, including electroencephalogram (EEG), penile plethysmography (PPG), and eye-tracking (n=10), (3) cognitive/behavioral (n=13), and (4) neuroimaging/neurofunctional (n=22), including fMRI and PET scan. Of the total 39 studies reviewed, 13 studies utilized fMRI as part of their methodology. Among these, 11 studies reported statistically significant findings. A comprehensive summary of the identified biomarkers is presented in Tables 1–4.

Genetic, epigenetic and neuroendocrinal biomarkers

Three studies investigated genetic and/or epigenetic biomarkers in pedophilia (40–42). Preliminary findings suggested involvement of epigenetic serotonergic system dysregulation, specifically indicating downregulation with alterations in 5HT3A (increased methylation) and SLC6A4 (reduced methylation) in subjects with a pedophilic sexual preference. Studies on the dopaminergic system reported no significant associations (40, 41).

Genetic and neuroendocrine studies suggest a potential link between epigenetic alterations in the serotonergic and testosterone systems, with lower testosterone levels and signs of prenatal androgen exposure observed in pedophilic individuals.

Neuroendocrine markers were assessed in three studies (19, 20, 42), revealing lower mean testosterone levels in pedophilic individuals compared to controls and indications of elevated prenatal androgen exposure in child sexual offenders compared to non-offending pedophiles and controls. One study identified methylation of the androgen receptor gene, in conjunction with reduced peripheral testosterone levels (42).

Physiological biomarkers (EEG, PPG, eye tracking)

Ten studies assessed physiological biomarkers, including brain responses (EEG, PPG) and eye tracking (19, 20, 43–50), reporting various physical and neurophysiological anomalies. Among the physiological biomarkers explored in the literature, minor physical anomalies (MPAs) have been identified as potential neurodevelopmental markers of pedophilic interest. In a study by Dyshniku et al. (43), MPAs were assessed using the Waldrop Physical Anomaly Scale, which quantifies 18 specific anomalies, including fine electric hair, hair whorls, abnormal head circumference, epicanthus, malformed ears, furrowed or irregular tongue, high/steepled palate, curved fifth finger, single palmar crease, and various toe anomalies.

Findings indicated increased minor physical abnormalities, elevated craniofacial-to-peripheral anomalies ratio (43), shorter leg length (45), higher rates of non-right or ambiguous handedness (44), as well as attentional control and greater sexual arousal ratings and erectile responses to undressed versus clothed child (visual sexual stimuli), suggesting dysfunction in prefrontal cortex and error processing areas (19, 20).

Regarding eye-movement variables, findings included shorter entry time to child stimuli and longer relative fixation time on adult stimuli (46), reduced attentional control (47, 48), and impaired executive functioning on interference tasks (47).

Cognitive/behavioral biomarkers

Cognitive impairments, especially in memory and executive functions, are commonly observed in pedophilia, with specific differences found between child sexual offenders and non-offenders, as well as convicted versus non-convicted offenders.

Thirteen studies explored cognitive and behavioral biomarkers (16, 22, 23, 25, 26, 38, 39, 51–56). Most found significant impairments in IQ, memory (immediate and delayed), visuospatial/constructional abilities, processing speed (slower visual performance, slower reaction time, less accurate visual target discrimination, visual-motor integration, processing speed), and set-shifting and executive function (response inhibition, attention and impulse control) (16, 23, 38, 39, 51, 52, 54, 56). One study, however, reported better performance on verbal memory and visual discrimination in participants with pedophilia (54).

Moreover, four studies showed that pedophilic child sexual offenders compared to pedophilic non-child sexual offenders, had lower IQ, poorer inhibition ability, more working memory errors, greater risk-taking behavior and higher interference susceptibility (25, 26, 53, 55). One study reported differences between convicted and non-convicted child sexual offenders in sexual age orientation, offense patterns (number of delicts) and victim profiles (number of male victims, age of female victims) (22).

Neuroimaging/neurofunctional biomarkers

Neuroimaging studies highlighted significant structural and functional brain differences in pedophilia, with evidence of altered connectivity, volume reductions, and abnormal brain activation patterns, particularly in areas related to emotional regulation, cognitive control, and sexual behavior. Specifically, twenty-two studies applied neuroimaging techniques (16–29, 32–39). Structural findings included reduced intracranial volume, cortical thickness and volume of white matter, smaller hippocampi and nuclei accumbens and abnormalities in cortical surface area (16, 26). Diffusion tensor imaging (DTI) studies found elevated fractional anisotropy (17), increased amygdala (prefrontal cortex connectivity) supporting models of disinhibited aberrant sexual impulses and impaired higher-order cognitive control (33), while one study reported lower fractional anisotropy, particularly in the corpus callosum (26).

The fMRI results showed altered activation in response to visual child stimuli in regions, such as the right inferior temporal cortex, which are associated with sexual arousal (erection) (19, 20, 29). Other studies reported atypical activations in networks related to moral judgment, such as the left temporo-parietal-junction, left posterior insular cortex, posterior cingulate gyrus and precuneus (27), while others in networks related to motivating behaviors, such as nurturing (left anterior insular cortex, supplementary motor cortex, and dorsolateral prefrontal areas) (32). Dysregulation functional connectivity with the default mode network, including deactivation of some regions, and regional differences (increases and decreases) in the frontoparietal network were also reported (17, 18, 23). Additionally, GABA reductions in the dorsal anterior cingulate cortex, a region linked to executive control process, were associated with low self-control and ADHD-like symptoms (34). However, not all studies found significant differences between pedophilic and teleiophilic individuals (21, 22, 25, 28).

Furthermore, comparative imaging studies of offending (P+CSO) versus non-offending (P-CSO) pedophiles revealed reduced resting-state functional connectivity in both the default mode and limbic network in P+CSO, especially in the left amygdala and orbitofrontal and anterior prefrontal regions (24). Additional findings in P+CSO group included smaller hypothalamus per side (37) and reduced activity in the a) medial parietal cortex, including the left caudal posterior cingulate and left superior frontal cortex (25), b) right dorsolateral prefrontal cortex (indicating impaired emotional regulation) (38), and c) left precuneus. Conversely, P−CSO individuals demonstrated increased activation and enhanced connectivity between regions implicated in cognitive empathy (left anterior cingulate cortex) (36). Additionally, P+CSO group showed a significantly reduced relative gray matter volume in the right temporal pole (35), and higher interference susceptibility, as well as hyperactivation in the left superior parietal cortex and precentral gyrus/supramarginal gyrus, therefore indicating potential difficulties to reallocate attention away from dominant tendencies (39).

Synthesis of results

Across domains, the reviewed literature indicated that multiple biomarkers may contribute to the identification and understanding of pedophilia. Genetic and epigenetic studies suggest involvement of neuroendocrine markers, i.e., serotonergic and testosterone systems. Physiological markers, including EEG, PPG, and eye-tracking, showed deviations in physical development, attentional control, and sexual arousal responses. Cognitive findings point to impairments in memory and executive function, with distinctions observed between offending and non-offending groups. Neuroimaging studies consistently highlighted structural and functional brain abnormalities in regions associated with emotional regulation, cognitive control, and sexual behavior. A detailed summary of study findings is provided in Tables 1–4.

Discussion

To our knowledge this is the first comprehensive review to synthesize existing data on biomarkers associated with pedophilia. By mapping findings across genetic, physiological, cognitive, and neuroimaging domains, the present review presented a structured overview of the current scientific landscape and identified important gaps that hinder the development of reliable diagnostic or risk-related biomarkers in the field. Overall, the present findings highlighted both the promise and complexity of identifying neurobiological correlates in pedophilia, while revealing the need for coordinated, ethically sound, and methodologically rigorous further research.

Among the four biomarker categories reviewed herein, neuroimaging and neurofunctional studies dominated the research field. These consistently reported alterations in brain structure and function, including reduced intracranial volume, cortical surface area abnormalities, and white matter volume differences. Functional neuroimaging findings reported divergent brain activation patterns to visual sexual stimuli, altered processing in moral reasoning and nurturing-related brain regions, and disrupted connectivity within the default mode network and frontoparietal networks. Notably, differences in brain structure and function (functional connectivity, brain activation, and gray matter volume) observed between individuals with pedophilic disorder who committed offenses and those who did not, suggesting potential neural correlates of behavioral control or risk factors for offending.

Cognitive and behavioral studies revealed a profile marked by deficits in IQ, memory, attention, and executive functioning. Lower IQ (working memory), greater susceptibility to interference and risk-taking behavior, and poorer inhibition performance were more pronounced among individuals with pedophilic disorders who committed child sexual offences, compared to those who did not. These impairments may point to broader neuropsychological vulnerabilities related to impulse regulation and decision-making. However, isolated findings of intact or even enhanced verbal memory suggest heterogeneity within this population, emphasizing the need for nuanced subgroup analyses.

Physiological biomarkers identified in EEG, plethysmography and eye-tracking studies showed promising data in identifying attentional and arousal patterns specific to pedophilic interests. Reported differences included increased physical abnormalities, atypical handedness, and shorter leg length. These may reflect underlying neurodevelopmental anomalies. In addition, eye-tracking data indicate shorter gaze latency toward child stimuli and reduced attentional control, while EEG findings point to diminished early frontal responses and altered error processing—both suggestive of atypical neural reactivity during sexual or executive tasks.

Genetic, epigenetic, and neuroendocrine biomarkers remained understudied, though early evidence suggested potential epigenetic alterations in the serotonergic and testosterone systems, while findings related to the dopaminergic system remained inconclusive. Specifically, findings included reduced peripheral testosterone levels, signs of elevated prenatal androgen exposure, and methylation changes in genes related to serotonin transport. While preliminary, these results suggest that hormonal and epigenetic factors may contribute to the biological underpinnings of pedophilia.

Despite these advances, no single biomarker demonstrated sufficient sensitivity or specificity to support clinical diagnostic use. Instead, findings across domains may be best understood as potential contributors to risk stratification, pathophysiological insight, or future treatment personalization. Overall, pedophilia is a complex and heterogeneous condition, varying widely in age of attraction, degree of behavioral control, comorbidity profiles, and offending history. These individual differences seem to contribute to inconsistent biomarker findings and complicate efforts to generalize across study populations.

Limitations

This review is subjected to several methodological constraints. While the decade-based publication restriction was applied to capture up-to-date biomarker research, it may have excluded foundational or earlier relevant studies. Moreover, excluding non-English literature may have limit the scope and introduce a potential language bias. Additionally, reliance on title and abstract screening during the selection of sources of evidence may have led to the inadvertent exclusion of relevant studies where biomarker relevance was only evident in full-text content.

The reviewed studies, also, present numerous limitations. Firstly, the study samples consisted exclusively of males, which limits the generalizability of the findings to women. Additionally, while some studies included relevant confounders such as sex, age, IQ/education, psychiatric morbidity, left-handedness, psychotropic medication, drug/alcohol use, and sexual orientation, not all studies controlled for these variables comprehensively. This lack of control for confounders can introduce bias and affect the validity of the results. Moreover, the included studies varied widely in methodology and reporting standards. This heterogeneity posed challenges for consistent data extraction and synthesis. Specifically, there was significant heterogeneity in the diagnosis of pedophilia and inconsistencies regarding the operational definitions of pedophilia across studies (e.g., DSM-5 criteria vs. ICD-11 or offense-based classification), which can lead to variations in the findings.

Differences were also noted in relation to neuroimaging protocols, and varied tasks used in cognitive or physiological assessments. The heterogeneity in study samples, including variations in the severity and characteristics of pedophilic behavior, further complicates the interpretation of results. Many studies also had small sample sizes, which reduces the statistical power and the ability to detect significant differences or associations. Furthermore, specific biomarkers were not consistently investigated across studies, and some biomarkers were not examined at all, leading to gaps in the understanding of the neurobiological underpinnings of pedophilia.

Future directions

These limitations highlight the need for more rigorous and standardized research methodologies in future studies to enhance the robustness and applicability of the results. By addressing these limitations, future research can enhance the robustness, validity, and applicability of findings, ultimately contributing to a better understanding of pedophilia and possibly informing effective interventions. Collaborative efforts across disciplines are essential, with adequate sample size in well characterized populations has the potential to advance biomarker research and improve diagnostic accuracy, treatment outcomes, and risk assessment for individuals with pedophilic disorders. Crucially, longitudinal designs and replication studies are needed to test the reliability and prognostic value of proposed biomarkers over time. Ultimately, for any biomarker to be used clinically, it must demonstrate a statistically significant relationship to a defined clinical endpoint, a causal or mechanistic link, and adequate sensitivity and specificity, validated through large-scale, preregistered trials.

The use of integrative methods using multimodal approaches that combine cognitive, neuroimaging, physiological, and genetic/epigenetic measures to provide a holistic understanding of pedophilia would be valuable. Specifically, future research should aim for larger, well-characterized samples, preferably through multicenter collaboration. Standardized diagnostic criteria and consistent measurement protocols would improve replicability. Applying the Research Domain Criteria (RDoC) approach may yield novel insights and facilitate biomarker development, also allowing researchers to study pedophilic traits dimensionally across multiple neurobiological and behavioral domains, rather than solely within categorical diagnoses. Although none of the current biomarkers are ready for diagnostic implementation, the integration of multiple biomarker modalities—such as combining neuroimaging, cognitive, physiological, and genetic/epigenetic data—may enhance the predictive accuracy of risk assessment tools and contribute to a more precise understanding of the disorder. Advanced analytical techniques, including machine learning and multivariate pattern analysis, could help identify meaningful subtypes and predict clinically relevant outcomes. Importantly, any translational effort must be grounded in strong ethical principles. The use of biomarkers to identify pedophilic interests raises complex questions regarding consent, privacy, potential stigma, and the risk of misuse. As such, biomarker research must prioritize not only scientific validity but also legal, clinical, and human rights safeguards.

Conclusion

This review offers the first comprehensive synthesis of biomarkers in pedophilia, identifying several promising biological systems potentially implicated in the pathophysiology of the disorder. While significant strides have been made, especially in neuroimaging, major methodological, ethical, and interpretive challenges remain. A multimodal, interdisciplinary, and ethically grounded approach will be critical to advancing this complex and sensitive field.

Data availability statement

The original contributions presented in the study are included in the article/Supplementary Material. Further inquiries can be directed to the corresponding author.

Author contributions

MK: Conceptualization, Formal analysis, Investigation, Methodology, Writing – original draft, Writing – review & editing, Data curation. AE: Data curation, Writing – original draft, Writing – review & editing, Investigation. AC: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Supervision, Validation, Writing – original draft, Writing – review & editing.

Funding

The author(s) declare that no financial support was received for the research and/or publication of this article.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision.

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Supplementary material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpsyt.2025.1627198/full#supplementary-material

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