1. Introduction

Age-classification through biomarkers refers to the use of biological indicators to estimate a person's age, biological maturity, or stage of development and then use that information to determine their legal status, rights, eligibility, or responsibilities.

Traditional legal systems usually classify individuals according to their chronological age—the time elapsed since birth. Biomarker-based classification introduces another possibility: using biological measurements to estimate how old a person appears to be biologically, regardless of their actual date of birth.

This raises important questions in constitutional law, medical jurisprudence, criminal justice, immigration, employment, sports regulation, child protection, privacy, and human rights.

Central legal issue: Can the state or another decision-maker use biological evidence to classify a person into an age-based legal category when that evidence conflicts with their documented chronological age?

The answer depends on the governing law, the purpose of the classification, the scientific reliability of the test, procedural safeguards, and the consequences for the individual.

A crucial distinction is that age estimation through biomarkers is not one uniform scientific technique. Different tests measure different characteristics, and none should automatically be treated as a precise biological clock.

2. Meaning and scientific foundations

A. Chronological age versus biological age

Chronological age

The person's age calculated from their date of birth. It is ordinarily the principal legal standard for majority, voting eligibility, criminal responsibility thresholds, and many other age-dependent rights.

Biological age

An estimate of physiological development or ageing based on selected biological characteristics. Two people with the same chronological age can have different biological profiles.

Legal age classification

A determination of the legal category into which a person falls, such as child or adult. It is a legal conclusion, not simply a laboratory result.

For example, a person whose documents indicate that they are 17 may have skeletal development that resembles the average development of an older person. That finding does not, by itself, establish that the person is legally 18.

Similarly, an older adult whose biological markers suggest unusually slow ageing does not thereby regain the legal rights or status of a younger person.

B. Major types of biomarkers used for age estimation

Important distinction: A biomarker can be useful for estimating age without being sufficiently reliable to decide an individual's legal status. Scientific validity for a research purpose is not necessarily the same as legal suitability for a high-stakes decision.

3. Legal framework in India

In India, biomarker-based age classification is particularly important in determining whether an accused person is a child in conflict with law, whether a person qualifies for child-protection measures, and whether age-related evidence is sufficient for a legal finding.

The key principle established by the Supreme Court is that medical age estimation is generally an evidentiary aid, not an automatic substitute for legally prescribed age-determination procedures.

A. Juvenile Justice (Care and Protection of Children) Act, 2015

Section 94 governs the presumption and determination of age for purposes under the Act.

Broadly, the provision establishes a hierarchy of evidence:

The date-of-birth certificate from the school, or the matriculation or equivalent certificate from the relevant examination board, where applicable under the statutory wording.

A birth certificate issued by a corporation, municipal authority or panchayat.

In the absence of the specified documents, an age determination through the prescribed medical examination or test ordered by the competent authority.

The statutory order matters. A medical examination should not casually displace the documentary evidence that the law gives priority to.

The precise applicability of each document and the procedure must be assessed under the current statutory text and relevant judicial decisions. In particular, the Supreme Court's decision in Rajni v. State of Uttar Pradesh (2025) addresses when a medical examination can be ordered under Section 94(2).

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B. Constitutional principles

Several constitutional guarantees may be implicated when the government uses biomarkers to classify age.

These provisions do not establish a general prohibition on medical age assessment. Instead, they help determine whether a particular system is lawful, fair, proportionate and adequately protective.

For instance, if a government authority classifies an undocumented young person as an adult solely because their bone development appears advanced, despite conflicting records and an acknowledged margin of error, the decision may raise questions about fairness and arbitrariness.

C. Other relevant legislation

The legal framework depends on the purpose of the test:

Protection of Children from Sexual Offences Act, 2012 (POCSO): age can be decisive to the application of statutory protections.

Bharatiya Nagarik Suraksha Sanhita, 2023: procedural questions in criminal proceedings must be considered alongside applicable age-determination rules.

Immigration and refugee law: age assessments can determine access to child-specific accommodation, guardianship and procedural safeguards.

Digital Personal Data Protection Act, 2023: the collection and processing of identifiable biomarker data may raise data-protection questions, subject to the Act's commencement, applicable provisions, rules and exemptions.

Employment, education and sports regulations: age-related eligibility rules may require reliable evidence, but the governing statute or policy determines which evidence is legally acceptable.

4. Landmark Indian case laws

The following cases provide the central legal principles for evaluating biomarker evidence. Most concern skeletal or radiological age estimation rather than modern epigenetic clocks; their reasoning is relevant by analogy, but they do not directly decide the legality of every new biomarker technology.

Case 1: Babloo Pasi v. State of Jharkhand (2008)

Supreme Court of India · (2008) 13 SCC 133

Facts and issue: The case concerned a claim of juvenility and the evidence required to determine whether the accused was below the legally relevant age. The evidence included medical age estimation and other material.

Legal principle: The Court explained that there is no universal formula that can establish a person's age in every case. Medical evidence is useful but is not conclusive; it must be assessed with other relevant evidence.

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Relevance to biomarker classification:

Suppose a laboratory reports that a person's biological age is consistent with 18 years or older. Under the reasoning in Babloo Pasi, that report should not automatically decide legal adulthood. The decision-maker must consider the applicable legal hierarchy of evidence, the report's reliability and the surrounding evidence.

Significance: This case is a foundational authority against treating medical age estimation as infallible.

Case 2: Ramdeo Chauhan alias Raj Nath v. State of Assam (2001)

Supreme Court of India · (2001) 5 SCC 714

Issue: The evidentiary value of an X-ray ossification test in determining age.

Legal principle: Radiological examinations may provide useful information, but they cannot establish the exact date of birth with complete accuracy. Biological development can vary among individuals and populations.

The Court's reasoning recognises that skeletal development is affected by factors including nutrition, environment and individual variation.

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Application to modern biomarkers:

The same caution is relevant when evaluating an epigenetic clock, telomere measurement or machine-learning age estimate. A statistical association between a biomarker and age does not establish that the method can precisely classify a particular individual at a legal threshold.

However, the evidentiary treatment of a new technology must also account for its own validation studies rather than assuming that all biomarkers have the same limitations as X-rays.

Case 3: Vishnu v. State of Maharashtra (2006)

Supreme Court of India · (2006) 1 SCC 283

Issue: Whether an expert medical opinion estimating age should necessarily be accepted over other evidence.

Legal principle: Expert medical opinion does not automatically override other relevant evidence. In the context discussed by the Court, the ossification estimate was not treated as scientifically conclusive merely because it came from a medical examination.

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Relevance: Biomarker-based classification should distinguish between:

The scientific result produced by the test.

The expert's interpretation of that result.

The legal conclusion that the person is above or below a statutory age threshold.

These are three separate stages, and an error at any stage can affect the final decision.

Case 4: State of Madhya Pradesh v. Anoop Singh (2015)

Supreme Court of India · (2015) 7 SCC 773

Legal principle: Ossification testing is not the sole criterion for determining age.

The case reinforces the principle that medical evidence must be assessed alongside other relevant evidence rather than being treated as an independent and conclusive determination.

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Application: If a biometric system estimates that a student is 18, but valid documentary evidence indicates that the student is 17, the administrator must follow the governing legal procedure. A numerical output from the system is not, by itself, authority to override the prescribed evidence.

Case 5: Mukarrab v. State of Uttar Pradesh (2017)

Supreme Court of India · (2017) 2 SCC 210

Issue: Whether medical evidence, including ossification testing, could conclusively establish age.

Legal principle: The Court reiterated that ossification testing cannot be regarded as conclusive for determining age, particularly given the difficulty of precise age estimation and the need to consider the wider evidentiary record.

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Significance: This authority is particularly useful when challenging an administrative or judicial decision that treats a biological estimate as an exact age.

Case 6: Manoj @ Monu @ Vishal Chaudhary v. State of Haryana (2022)

Supreme Court of India · decided 15 February 2022

Legal principle: The Court discussed the established limitations of medical age determination and reaffirmed that medical evidence must be considered with the other evidence relevant to age.

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Application: A person contesting an age classification can question the methodology, the interpretation of the report, and the way the authority reconciled medical findings with documentary evidence.

The case also illustrates why a range of estimated ages should not casually be converted into a single exact age without justification.

Case 7: Vinod Katara v. State of Uttar Pradesh (2022)

Supreme Court of India · 2022 SCC OnLine SC 1204

Legal principle: Bone ossification testing is not an exact science. The Court discussed the effect of individual differences in skeletal growth and the margin of error associated with radiological age estimation.

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Relevance to modern technologies: The judgment supports a broader evidentiary safeguard: the limitations of the scientific method must be made visible to the decision-maker.

A system that produces “18.2 years” should not be presumed more accurate than a medical assessment reporting an age range. Decimal precision in a computer-generated estimate does not establish equivalent scientific certainty.

Case 8: Rajni v. State of Uttar Pradesh (2025)

Supreme Court of India · 2025 INSC 737 · decided 20 May 2025

Issue: When a Juvenile Justice Board can order a medical examination for age determination under Section 94(2) of the Juvenile Justice Act.

Legal principle: The decision addresses the statutory sequence for age determination and holds that the Board cannot bypass the prescribed documentary evidence to order a medical test where the relevant statutory certificate exists.

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Significance: This case is particularly important because it moves beyond the general reliability of medical evidence and addresses the legal authority to obtain it in the first place.

For biomarker-based classification, two separate questions therefore arise:

Is the biomarker scientifically reliable enough for the proposed purpose?

Does the authority have legal power to require or use that test in the circumstances?

A scientifically useful test can still be legally impermissible if the authority disregards the governing statutory procedure.

5. Comparative international case law

Indian decisions establish important evidentiary principles. International decisions and human-rights guidance add a further dimension: the dignity, privacy, bodily integrity and protection of children subjected to age assessment.

A. French Constitutional Council — Decision No. 2018-768 QPC (2019)

The French Constitutional Council examined provisions concerning medical examinations used to assess the age of young people claiming to be minors.

The issue included the use of bone examinations and the safeguards required when medical findings are used to decide whether a person is a child.

The decision recognised the significance of the scientific limitations of such examinations and considered the legal safeguards attached to their use.

Relevance: A state may have a legitimate interest in verifying age, but the use of medical testing must be assessed against constitutional protections and the safeguards governing the procedure. The decision does not establish that every form of biomarker-based age estimation is constitutionally valid.

B. European asylum age-assessment practice

European asylum procedures provide useful comparative material because age classification can determine access to guardianship, child-specific accommodation and procedural protections.

The European Union Agency for Asylum has described approaches requiring multidisciplinary assessments, scientific justification, impartiality and attention to the best interests of the child. It also reports concerns about the reliability of bone and dental assessments and the treatment of uncertainty.

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The legal lesson is that age assessment should not necessarily be reduced to a single physical or medical indicator.

C. International human-rights guidance

Guidance discussed in United Nations human-rights materials recommends that age assessments be undertaken when there are serious doubts about a person's stated age, using a multidisciplinary approach rather than relying solely on physical appearance. Where material uncertainty remains, the benefit of the doubt should be considered.

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This is particularly relevant to unaccompanied children seeking international protection.

Important qualification: International guidance is not automatically binding domestic law in India. Its legal force depends on the applicable treaty obligations, domestic legislation and the way courts interpret relevant rights.

6. Legal issues raised by modern biomarkers

The traditional cases primarily concern radiological, dental and skeletal assessment. Modern biomarkers raise additional questions that require separate legal analysis.

1. Scientific validity

Has the biomarker been validated for the specific population, tissue type, age range and legal threshold? A model developed to estimate average biological ageing may not be valid for determining whether a person is 17 or 18.

2. Privacy and bodily integrity

DNA methylation, genetic information and other biological data may be highly sensitive. Collection, storage, secondary use and disclosure require appropriate legal authority and safeguards.

3. Equality and discrimination

A test may perform differently across populations, sexes, health conditions or nutritional backgrounds. A system that disproportionately misclassifies particular groups may raise equality and fairness concerns.

4. Transparency and contestability

A person affected by an adverse decision should, subject to applicable law, be able to understand the evidence, challenge its reliability and seek an independent review.

5. Proportionality

The more serious the consequences of misclassification, the stronger the justification and procedural safeguards should be. A test used for a low-stakes research estimate should not automatically be suitable for criminal prosecution or the removal of child-protection benefits.

7. Application in different legal fields

The governing law may prescribe a particular form of evidence. Biomarkers cannot automatically replace that evidence simply because they are technologically advanced.

8. Hypothetical legal problem

Consider the following situation.

A young person claims to be 17 years old and provides a birth certificate. An authority commissions a biological age assessment, which estimates an age of 18–20 years. The authority then treats the individual as an adult without investigating the discrepancy.

The legal analysis would proceed as follows.

Examine the governing statute. Determine whether the authority was permitted to order a medical test and whether the law prescribes a hierarchy of evidence.

Examine the scientific report. Identify the method, reference population, uncertainty interval, validation data and limitations.

Evaluate the documentary evidence. Verify the birth certificate and consider any legally relevant reason for doubting its authenticity or accuracy.

Assess procedural fairness. Determine whether the person could examine and challenge the evidence, obtain expert assistance and seek review.

Consider the consequences. Determine whether the decision improperly deprived the person of protections attached to childhood.

Apply the relevant remedy. Depending on the governing law, a competent authority or court may set aside the decision, require reconsideration or order a lawful age determination.

In an Indian juvenile-justice context, Babloo Pasi and Rajni would be particularly relevant: the former on the evidentiary limits of medical opinion, and the latter on the statutory requirements governing when medical testing may be ordered.

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The hypothetical does not mean that a birth certificate is unchallengeable in every situation. Its evidentiary status and any challenge to it must be determined under the applicable law.

9. Proposed regulatory framework for biomarker-based age classification

A sound legal framework should include the following protections.

Purpose limitation: Define the specific legal purpose for which the biomarker may be used.

Validation: Require independent scientific validation for the relevant population and threshold.

Documentary priority: Follow statutory rules concerning birth and educational records.

Proportionate testing: Use the least intrusive suitable method and avoid unnecessary testing.

Uncertainty disclosure: Require reports to disclose limitations and uncertainty rather than present estimates as exact ages.

Human review: Prevent an automated estimate from becoming an unchallengeable legal decision.

Data governance: Limit access, retention and secondary use of biological data.

Independent challenge: Provide a meaningful opportunity to question the method, report and final decision.

Protection against discriminatory effects: Audit error rates across relevant populations.

Special safeguards for children: Give proper weight to child welfare and applicable rules concerning uncertainty.

These are proposed regulatory safeguards, not a claim that every item is already a universal statutory requirement.

10. Critical analysis

Biomarker-based classification presents a tension between administrative efficiency and individual rights.

On one hand, reliable scientific techniques may help authorities investigate disputed ages, identify inconsistencies and make decisions where documentary evidence is unavailable.

On the other hand, biological development is not identical to chronological age. If a government converts a probabilistic estimate into a rigid legal classification, a measurement error can become a denial of liberty, education, protection or other rights.

The danger is particularly acute when the law establishes a sharp threshold. An estimated age of 17 years and 11 months and an estimated age of 18 years and 1 month may be statistically difficult to distinguish, yet the legal consequences could be substantial.

Three principles should therefore guide the law:

Scientific evidence must be fit for its intended legal purpose.

Legal status must be determined under the applicable rules of evidence and procedure.

The consequences of uncertainty must be allocated according to the governing law and relevant rights protections, not concealed by technological precision.

A system should also distinguish biological ageing from developmental maturity. Neither a DNA-based age estimate nor a measurement of physical maturity directly establishes a person's capacity, culpability or competence for every legal purpose.

11. Conclusion

Age-classification through biomarkers is an emerging issue at the intersection of forensic science, constitutional law, medical ethics and data protection.

Indian Supreme Court decisions—including Ramdeo Chauhan, Babloo Pasi, Vishnu, Anoop Singh, Mukarrab, Manoj Chaudhary, Vinod Katara and Rajni—provide important principles for assessing medical age evidence and following the legally prescribed process. In particular, they caution against treating skeletal age estimation as a precise or conclusive determination and emphasise the importance of the applicable evidentiary framework.

Modern epigenetic and other molecular biomarkers may provide additional information, but their legal acceptability must be assessed individually. The older judgments should not be treated as having directly adjudicated technologies that were not before those courts.

The central conclusion is that a biomarker may provide evidence about age, but it does not independently create a person's legal age or determine their rights. A defensible classification requires lawful authority, scientifically appropriate evidence, procedural fairness and safeguards proportionate to the consequences.

Selected authorities and further reading

Babloo Pasi v. State of Jharkhand, (2008) 13 SCC 133. Read judgment

Manoj @ Monu @ Vishal Chaudhary v. State of Haryana (2022). Read judgment

Rajni v. State of Uttar Pradesh, 2025 INSC 737. Find the judgment

European Union Agency for Asylum, Age assessment of minors. Read comparative guidance

United Nations human-rights material on age assessment and safeguards. Read guidance