Connecticut updated its marriage laws in 2025 to explicitly prohibit first cousin marriages starting October 1, 2025. Prior to this change, first cousin marriages were legal, but closer relatives have long been banned.
Prohibited Degrees of Consanguinity
Connecticut General Statutes § 46b-21 forbids marriages between parent, grandparent, child, grandchild, sibling, parent’s sibling (aunt/uncle), sibling’s child (niece/nephew), stepparent, or stepchild. These unions are void from the start.
A 2025 amendment via HB-06918 added first cousins to this list, effective October 1, 2025, under new § 46b-20a. It states no person may knowingly marry their first cousin on or after that date.
Distant relatives like second cousins or first cousins once removed remain permitted.
Impact of the 2025 Ban
The law targets first cousins specifically, making such marriages unlawful prospectively. Pre-2025 first cousin marriages are unaffected unless challenged on other grounds.
Couples must affirm eligibility when applying for a license at a town clerk’s office, now including no first cousin relation post-October 1, 2025. Minimum age is 18.
Exceptions and Special Cases
- Double first cousins: Treated as first cousins; prohibited after October 1, 2025.
- Adoptive or step-relations: Bans apply only to listed blood or affinity relations; non-blood cousins are fine.
- Out-of-state marriages: Connecticut recognizes valid out-of-state unions under full faith and credit, but residents cannot enter prohibited marriages here.
Violations render the marriage void.
Penalties for Violations
Knowingly entering a prohibited marriage, including first cousin post-2025, is illegal. Specific penalties aren’t detailed in the statute but align with general marriage fraud or bigamy offenses, potentially misdemeanors with fines or invalidation.
Prosecutions are uncommon without fraud or coercion.
Comparisons with Other States
Connecticut joined states banning first cousin marriage after its 2025 shift.
| Category | Examples |
|---|---|
| Fully Legal | California, New York, Alabama |
| Banned (like new CT) | Texas, Kentucky, now Connecticut |
| Restricted (e.g., age/infertility) | Arizona, Wisconsin |
As of 2026, about 25 states ban first cousin marriage outright.
Practical Advice for Couples
First cousins cannot legally marry in Connecticut after October 1, 2025—consider neighboring states if needed. Always verify with a town clerk or family law attorney for your situation. Check the Connecticut General Assembly site for any 2026 updates.
SOURCES :
- https://en.wikipedia.org/wiki/Cousin_marriage_law_in_the_United_States
- https://www.harwinton.gov/DocumentCenter/View/761/Marriage-License-Laws-August-2025












