Is It Legal to Marry Your First Cousin? Laws and Exceptions Explained

On January 14th, the LegalClarity Team had an article about cousin marriage:

The historical context of cousin marriage sheds light on current legal perspectives. Historically, cousin marriages were common among royal and noble families in Europe to consolidate power and wealth, a practice that influenced the permissive stance in some European countries.

In the United States, the legal approach has shifted over time. Initially, many states permitted cousin marriages, but the late 19th and early 20th centuries saw prohibitions influenced by the eugenics movement. This movement, which aimed to improve genetic quality, led to laws banning cousin marriages in several states due to concerns about genetic defects in offspring. These laws have been challenged over the years, with varying outcomes. For example, in the 1980 case of Zablocki v. Redhail, the U.S. Supreme Court reaffirmed the fundamental right to marry. While this case did not directly address cousin marriage, it has been cited in arguments for more permissive marriage laws.

Legal precedents in other countries also reflect a mix of historical and cultural influences. The United Kingdom’s Marriage Act of 1836 formalized the legality of cousin marriages, a stance that remains unchanged. In contrast, Germany’s Basic Law emphasizes the protection of family and marriage but adopts a cautious approach to consanguinity, requiring genetic counseling.