Sweden has moved to prohibit marriages between cousins and other close relatives after lawmakers approved a new legal framework that will take effect on July 1, 2026, marking a significant shift in the country’s family law policies.

The reform, passed by the Swedish parliament, expands existing restrictions on consanguineous marriage and places cousin marriages alongside other prohibited family unions. Once implemented, the law will make it illegal for individuals within defined degrees of kinship to marry under Swedish civil law.

Officials supporting the measure have argued that the change is intended to strengthen protections around family structure and reduce the potential social and medical complications associated with close-kin marriages. The legislation aligns Sweden with a broader European trend in which several countries have revisited long-standing rules governing marriage between relatives.

The new law also reflects growing political attention in Europe to integration policy, public health considerations, and evolving cultural norms surrounding marriage and family formation. Supporters of the ban have pointed to concerns raised in other European countries regarding hereditary health risks and the legal complexity of regulating cousin marriages in modern, diverse populations.

The legislation places Sweden among a smaller group of Western countries that have moved to formally restrict cousin marriage at the national level, rather than leaving the issue to regional or case-by-case regulation. Once in force, civil authorities will be required to ensure that marriages falling within the prohibited categories cannot be legally registered or recognized.

Sweden has previously maintained relatively liberal marriage laws compared to some of its European neighbors, but the new measure represents a notable tightening of family law policy.

The law’s implementation date of July 1, 2026, gives authorities time to adjust administrative systems and public registries, while also allowing for public awareness efforts ahead of enforcement.

As the deadline approaches, officials are expected to issue additional guidance clarifying how the restrictions will be applied and how existing or cross-border marriages will be treated under Swedish law.