As of 2025, it has been legal for first cousins to marry in Connecticut. The state, along with roughly 16 other states, has permitted cousin marriages without restrictions until very recently.
Connecticut law has traditionally prohibited marriage between close relatives such as parents, grandparents, siblings, children, and step-relations but did not explicitly prohibit marriage between cousins, making cousin marriage permissible by default.
New Legislation Prohibiting First-Cousin Marriage
However, starting October 1, 2025, a new law will come into effect banning marriage between first cousins in Connecticut. This legislation was introduced and signed into law in 2025, marking a significant change in the state’s marriage laws. The law explicitly makes it illegal for first cousins to knowingly enter into marriage with each other, adding them to the list of relatives who are prohibited from marrying.
Details of the Law and Its Scope
This new statute builds upon existing laws that already disallow marriages between other close relatives such as parents, grandparents, children, siblings, and various stepfamily members.
With this update, marriage between first cousins will also be void and prohibited. The law aims at regulating marital relationships to address concerns related to genetics, social norms, and cultural views on consanguinity (blood relation in marriage).
Reasons Behind the Ban
Proponents of the law argue that cousin marriage carries increased risks of certain genetic disorders in offspring due to the higher probability of inherited recessive conditions. The ban aligns Connecticut with many other states that restrict cousin marriages due to public health considerations and social policy objectives.
Discussions and hearings on the bill revealed mixed opinions, with opposition mostly based on cultural or religious grounds, as some families have longstanding traditions of cousin marriage without reported issues.
What This Means for Couples
Couples who are first cousins will no longer be able to legally marry in Connecticut starting October 1, 2025.
Marriages contracted before the effective date will remain valid unless challenged on other grounds.
Couples seeking to marry must ensure they are not within prohibited degrees of consanguinity under the updated law.
Legal consequences apply for knowingly entering a marriage that violates this prohibition, including the marriage being void.
Clarifications on Other Relatives
Connecticut has long prohibited marriage between closer relatives such as uncle-niece or aunt-nephew, but now the cousin ban explicitly extends this protection to first cousins as well. The law does not affect more distant relatives such as second cousins, where marriage remains lawful under current statutes.
Until late 2025, marrying a first cousin in Connecticut was legal, making the state one of the few that allowed such marriages without restriction. However, effective October 1, 2025, a new law will prohibit first cousins from legally marrying, placing Connecticut in line with many other states that restrict cousin marriage primarily due to genetic health concerns and evolving social norms. Couples in Connecticut who are related as first cousins should be aware of this legal change and plan accordingly.
Sources
(https://www.ctpost.com/connecticut/article/ct-cousin-marriage-legal-where-connecticut-20158492.php)
(https://www.ctinsider.com/connecticut/article/ct-cousin-marriage-legal-where-connecticut-20158492.php)
(https://www.cga.ct.gov/2025/fc/pdf/2025HB-06918-R000728-FC.pdf)
(https://www.cga.ct.gov/2025/sum/pdf/2025SUM00072-R01HB-06918-SUM.pdf)
(https://www.ctpost.com/politics/article/first-cousin-marriage-banned-connecticut-law-20395170.php)
