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Ius Sanguinis (principle of descent)
All information on the principle of descent (nationality law) that applies in Germany.
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what the “Ius Sanguinis” ( principle of descent ) is
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1. What is the “Ius Sanguinis” (principle of descent)?
2. Ius sanguinis in the case of an unmarried German father
3. Ius sanguinis and foundlings/children born in confidence
4. Naturalization and Ius Sanguinis
5. FAQ Ius Sanguinis
6. Conclusion: Ius Sanguinis
1. What is the “Ius Sanguinis” (principle of descent)?
The principle of jus sanguinis ("right of blood") refers to the principle of descent , according to which a child acquires German citizenship through descent from a German parent . This is legally regulated in Section 4 Paragraph 1 of the German Nationality Act (StAG) , which establishes acquisition by descent as the central basis for acquiring citizenship under German law. This contrasts with jus soli, where the place of birth is decisive. With jus sanguinis, only legal parenthood (e.g., of adopted children ) is relevant; biological parenthood is not mandatory. Proof of this descent is usually provided by German or foreign civil status documents, which, however, are not necessarily final and remain subject to rebuttal in administrative proceedings. In principle, the place of birth is irrelevant for acquiring citizenship by descent, so children of German parents automatically receive German citizenship both in Germany and abroad – subject to the specifics of generational boundaries .
For jus sanguinis to apply, at least one parent must possess German citizenship at the time of the child's birth. The decisive factor is who is legally considered the mother or father; this is determined by Sections 1591 et seq. of the German Civil Code (BGB) and Article 19 of the Introductory Act to the German Civil Code (EGBGB ), for example, in cases of births abroad or differing parentage arrangements. Special provisions also apply to individuals with German status under the Federal Expellees Act (BVFG) : They only pass on their citizenship to their child if they have already been issued a certificate pursuant to Section 15, Paragraph 1 or 2 of the BVFG. If such a certificate is not yet available, only the status of German status is passed on, not German citizenship itself.
2. Ius sanguinis in the case of an unmarried German father
Acquiring German citizenship by descent is straightforward for a child born to a German mother, as the child automatically receives citizenship at birth. The same applies if a German father is married to a foreign mother ( § 1592 No. 1 of the German Civil Code ). However, the situation is different if the father is German and the mother is foreign, and the parents are not married. In such cases, acquiring citizenship by descent depends on a valid acknowledgment of paternity or a court-ordered determination of paternity. Without this legal clarification, descent is not considered established – and the child does not initially acquire German citizenship by birth.
If paternity is acknowledged or legally established, this decision has retroactive effect "ex tunc," meaning it applies from the date of birth. However, for the child to acquire German citizenship, the acknowledgment or the application for a determination of paternity must have been submitted before the child's 23rd birthday (§ 4 para. 1 sentence 2 of the German Nationality Act). In addition to the child acquiring citizenship, the acknowledgment of paternity has further legal consequences: The foreign mother may thereby obtain a right of residence under § 28 para. 1 sentence 1 no. 3 of the German Residence Act (see family reunification ) or § 25 para. 5 of the German Residence Act in conjunction with Article 8 of the European Convention on Human Rights.
3. Ius sanguinis and foundlings/children born in confidence
The acquisition of German citizenship by descent (ius sanguinis) also includes special cases such as foundlings . A child found in Germany is presumed by law to be the child of a German citizen – and thus German – until their actual parentage is established ( § 4 para. 2 StAG ). While this presumption can be rebutted, it protects older minor children in particular when their origins cannot be definitively determined. If the actual parentage is later established, German citizenship can be revoked retroactively if neither parent is German.
Citizenship law treats children born through confidential births similarly. Since 2014, mothers in difficult circumstances have been able to give birth anonymously; the child also acquires German citizenship "as the child of a German citizen" as long as the mother's identity remains undisclosed. Only when the mother releases her data, or when the child, upon reaching the age of 16, asserts their right to access their parentage, can the actual parentage be clarified – with corresponding consequences under citizenship law. Until then, the child retains their German citizenship.
4. Naturalization and Ius Sanguinis
The principle of jus sanguinis means that descendants of German citizens automatically acquire German citizenship by descent – a separate naturalization procedure is not required in these cases. This acquisition by descent occurs by operation of law if at least one parent is German at the time of the child's birth.
However, in practice, cases of doubt can arise , particularly when German citizenship is alleged to have been "passed down" over several generations, for example, through German grandparents or great-grandparents. In such situations, it is often unclear whether the line of descent has actually led to continuous acquisition of citizenship. To clarify this question in a legally binding manner, the Nationality Act provides for the determination procedure according to Section 30 of the Nationality Act . This procedure serves to verify whether the person in question is already a German citizen – and thus ensures that the acquisition of citizenship according to jus sanguinis is correctly traced and confirmed.
5. FAQ
How does a child acquire German citizenship according to jus sanguinis?
A child automatically becomes a German citizen if at least one parent holds German citizenship at the time of birth. The place of birth is irrelevant. The sole determining factor is legal parenthood under German law.
Does jus sanguinis also apply to births abroad?
Yes. Children of German parents who are born abroad generally acquire German citizenship automatically. However, special rules apply under the so-called generational cut (§ 4 para. 4 StAG) if Germans are born abroad and subsequently have children there.
What happens when a German father is unmarried?
In this case, the child will only acquire German citizenship if the father legally acknowledges his paternity or if it is established by a court. This legal determination must be made before the child's 23rd birthday. If it is made in time, it is retroactive to the child's birth.
6. Conclusion
Juris sanguinis forms the core of German citizenship law and ensures that children of German parents automatically acquire citizenship at birth – regardless of where they are born. At the same time, experience shows that certain situations, such as unmarried fathers, births abroad, or foundlings, require special attention to clearly prove the acquisition of citizenship. For individuals who believe they have a claim to citizenship through German ancestry, jus sanguinis is an important instrument. In cases of doubt, the determination procedure under Section 30 of the German Nationality Act (StAG) provides the necessary legal certainty. One of our specialized lawyers will be happy to advise you on this matter.
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List of Sources (Paywall)
[1] Hailbronner/Kau/Gnatzy/Weber, Nationality Law, 7th edition 2022, § 30
[2] Oberhäuser in Hofmann, Ausländerrecht | StAG § 4 | 3rd edition 2023 (Paywall)
[4] Marx, Residence, Asylum and Refugee Law, 8th edition 2023
[5] Procedural guidelines for residence in Berlin (VAB), as of 18 February 2025, section S
[6] BMI, Preliminary application guidelines of the Federal Ministry of the Interior on the Nationality Act (VAH-StAG), as of 1 June 2015
[7] Section 4 of the Nationality Act in the consolidated version published in the Federal Law Gazette Part III, Classification Number 102-1, as last amended by Article 2 of the Act of 22 March 2024 (Federal Law Gazette 2024 I No. 104)