What Is Jus Sanguinis? Definition & Origins

Definition & Etymology: Jus sanguinis (Latin: “right of blood”) is a citizenship rule where nationality is granted based on descent from citizen parents, regardless of birthplace. According to Merriam-Webster, it means “a rule that a child’s citizenship is determined by its parents’ citizenship”. The European Migration Network defines “ius sanguinis” as nationality based on parents’ citizenship at birth or acquisition time.

Historical Evolution
Emerging from Roman and early modern continental legal traditions, jus sanguinis persisted in countries like Germany, Italy, and France into the 19th century. The 1860 codification of “jus soli versus jus sanguinis” marked a shift: European civil-law systems emphasized parentage, while British-origin jurisdictions stressed birthplace — a debate crystallized in the late 1800s by legal scholar Charles Demolombe.

The contrast was evident in the Franco-German 19th-century discourse: Fichte championed “blood-based nationality,” while Renan promoted civic territorial ties, leading to divergent national policies.

Modern Hybridity
Today, most states implement mixed nationality systems—combining jus sanguinis and jus soli. It’s rare for countries to rely solely on descent; many incorporate safeguards like ancestor generation limits and gender equality clauses.

Parentage Rules & Generational Limits

Countries around the world apply jus sanguinis in vastly different ways, particularly in terms of how descent can be passed from parent to child:

Unlimited Descent (Generationally Open)
Italy has long exemplified unrestricted descent-based citizenship. Under its 1912 law (as amended), Italian nationality may be passed down indefinitely—so long as each ancestor remained an Italian citizen at the time of their child’s birth. This expansive model grants eligibility to multiple generations of descendants without limitation.

Generational Cap (Limited Descent)
Canada, by contrast, enforces a strict “first-generation limit.” Children born abroad to Canadian citizens who themselves were born abroad do not automatically receive citizenship under normal circumstances. For example, a Canadian parent born in Canada may pass citizenship to a child born overseas, but if that child also spends their life abroad and has children abroad, those grandchildren do not automatically qualify—unless the parent lived in Canada for at least 1,095 days (about three years) before the child’s birth, under the proposed Bill C‑3.

Registration Condition (Deadline-Based Retention)
Germany operates under what could be described as “conditional descent.” Children born abroad to German parents hold German nationality only if the birth is formally registered at a German embassy or civil registry office before their first birthday—otherwise the entitlement is lost. This rule safeguards lineage while also imposing a precise administrative responsibility.

Historically, descent laws often favored patrilineal bloodlines, where only father’s nationality determined a child’s citizenship:

Italy: Before 1948, an Italian mother could not pass her citizenship to her child. Marrying a foreigner often resulted in her losing Italian nationality altogether; children born to Italian mothers and foreign fathers were not granted citizenship.

Even today, 24 countries continue to include some form of maternal descent limitation—with citizenship not consistently transmitted from the mother, potentially leading to statelessness.

Reforms underway:

Many nations have amended citizenship laws to allow gender-neutral transmission, in line with global gender-equality standards advocated by organizations like the UN’s CEDAW.

In Germany, the law now permits maternal descent on equal terms with paternal descent, though previous generations had to contend with male-line preference.

Strict adherence to jus sanguinis—without accompanying protections—can result in stateless children, especially when both parents are foreign-born in restrictive systems.

International frameworks have stepped in to address this:

UN Convention on the Reduction of Statelessness (1961)
This treaty requires contracting states to grant nationality to:

1. 1. Children born in the country who would otherwise be stateless.
   2. Children born abroad to at least one national parent—if they would otherwise remain stateless.
   3. Foundlings discovered within the state’s territory.

Specifically, Article 4 mandates descent-based citizenship if it prevents statelessness, and Article 2 ensures foundlings acquire national status by default.

Implementation in National Laws
To align with UN requirements, many countries have:

• Adopted conditional jus soli: grant citizenship if a child born locally would otherwise be stateless.
• Included foundling provisions: treating abandoned infants as nationals based on the state where they were found.
• Example: Germany offers jus sanguinis plus protections for children who would otherwise remain stateless, meeting international obligations.
• Canada confirms citizenship for abandoned children found before age seven, treating them as if born in Canada unless proven otherwise.