By a decision of the Turkish Constitutional Court (Anayasa Mahkemesi) published in the Official Gazette on 18 March 2026, paragraph 2 of Article 80 of the Criminal Procedure Code (Ceza Muhakemesi Kanunu, CMK) was annulled. The annulled provision was a rule that also covered the destruction, in certain circumstances, of genetic examination data obtained within the scope of criminal procedure.
This decision is not merely a technical procedural matter in terms of criminal investigations and prosecutions. Because genetic data contains highly sensitive information about a person’s identity, biological characteristics and family ties, it is directly connected with the confidentiality of private life, the protection of personal data and fair trial guarantees.
What Has the Annulment of CMK Article 80/2 Brought to the Agenda?
In criminal procedure, molecular genetic examinations may be carried out on samples taken from suspects, defendants, victims or other persons. Although these examinations serve the purpose of establishing the material truth, the nature of the results obtained requires them to be subject to strict legal safeguards.
The annulled CMK Article 80/2 provided a framework for the destruction of information obtained as a result of genetic examination. With the annulment of this provision, the following questions in particular have gained importance:
- Under what conditions may genetic examination data be retained?
- In which cases and by what procedure will it be destroyed?
- Who will be able to access this data?
- Will it be possible to use the data in other investigations or prosecutions?
- Is a legal basis emerging for the establishment of a central genetic data registry system in Turkey?
The answers to these questions must be assessed not only under the rules of criminal procedure, but also together with constitutional principles and the general framework governing the protection of personal data.
Why Is Genetic Data More Sensitive Than Other Personal Data?
Genetic data differs from ordinary identity or contact information. It may reveal a person’s biological characteristics, lineage and, in some cases, indirect information about family members. For this reason, it is considered special category personal data.
The core principles for processing such data are as follows:
- Legality: The purpose for which the data will be processed, the authority that will process it and the limits within which it will be processed must be clearly regulated.
- Purpose limitation: Genetic data obtained for the purposes of criminal procedure should, as a rule, not be used for other purposes.
- Proportionality: Genetic examination must be necessary and suitable for each investigation or prosecution.
- Retention period: Indefinite retention of data creates a risk of rights violations unless strong legal safeguards are in place.
- Access control: Access to genetic data must be limited to specific persons and specific legal purposes.
These principles are also indispensable for any possible genetic data registry system.
The Annulment Decision Does Not Automatically Establish a Genetic Data Registry
The annulment of CMK Article 80/2 does not, by itself, mean that a genetic data registry system has been established. If such a registry system is to be established, it must be based on a clear, foreseeable and detailed statutory regulation.
For such a system to be lawful, at least the following elements would be expected to be regulated:
- Purpose of the registry: It must be clear whether the data will be used only for specific and legitimate purposes, such as solving serious crimes.
- Scope: It must be specified whose data will be recorded and how distinctions will be made between suspects, defendants, convicted persons and victims.
- Retention and destruction regime: It must be clearly determined after which decision or process the data will be deleted.
- Access authority: The access limits of law enforcement, prosecutors’ offices, courts or expert institutions must be separately defined.
- Supervision and remedies: The rights of data subjects to learn whether their data is being retained, to request its deletion and to seek remedies against unlawful processing must be secured.
A broad database established without these elements could give rise to serious constitutional debates in terms of the confidentiality of private life and the protection of personal data.
The Balance Between Criminal Procedure and Personal Data Protection
The aim of establishing the material truth is important in criminal proceedings. However, this aim does not grant unlimited authority to restrict individuals’ fundamental rights and freedoms. Where genetic data is concerned, the balance becomes even more delicate.
This balance may be summarized by the following comparison:
| Criminal procedure need | Fundamental rights safeguard |
|---|---|
| Preservation of evidence | Data not being used for purposes other than those intended |
| Identification of the perpetrator | A retention regime consistent with the presumption of innocence |
| Solving repeat offences | Prohibition of indefinite and unlimited recording |
| Effective investigation | Judicial and administrative oversight |
Therefore, any new regulation on the retention or destruction of genetic data should be addressed not only as a technical forensic informatics issue, but also from the perspective of constitutional rights.
What Risks May Arise in Practice?
Following the annulment of CMK Article 80/2, transitional period debates may arise in practice. In particular, careful attention should be paid to how existing genetic examination data will be retained, in which files the destruction procedure will be applied and which rules will apply until a new statutory regulation is enacted.
The main areas of risk are as follows:
- Impairment of the right to personal data protection due to an uncertain retention period,
- The fate of data becoming controversial in cases such as acquittal or a decision that there are no grounds for prosecution,
- Lack of clarity regarding the limits on the use of genetic data in other files,
- Data security breaches causing consequences that are difficult to remedy,
- Failure to ensure uniform practice in relation to data subjects’ requests for information and deletion.
If a new regulation is introduced, these risks should be eliminated through clear and detailed provisions.
What Does This Mean in Practice?
The Constitutional Court’s annulment decision is an important turning point for the future of genetic data in criminal procedure. However, this decision does not by itself establish a central genetic data registry; such a system can be possible only with a clear statutory basis and strong safeguards.
The key conclusions are as follows:
- CMK Article 80/2 has been annulled; this reopens the debate on the destruction regime for genetic examination data.
- Genetic data should be treated as special category personal data of high sensitivity.
- For any possible genetic data registry, the purpose, scope, retention period, access and destruction rules must be clearly determined by law.
- During the transitional period, practitioners must pay particular attention to the principles of proportionality, purpose limitation and data security.
- When a new regulation is enacted, a reasonable balance must be struck between the effectiveness of criminal justice and fundamental rights safeguards.