Connecticut to Ban First-Cousin Marriages, Becoming 26th State to Outlaw the Union

Connecticut will prohibit marriages between first cousins effective Oct. 1, making the state the 26th in the nation to outlaw the union. The measure cleared the General Assembly earlier this year with broad bipartisan support. Under the bill, no person may knowingly marry that person’s first cousin.

Lawmakers said the change closes a long-standing gap in state law. Existing statutes already bar marriages within immediate family, including siblings and parent-child relationships; the cousin link had remained legally unaddressed until now. Supporters argue that more stringent prohibitions reflect contemporary science and public health concerns.

State Rep. Devin Carney, a Republican who represents Old Saybrook, sponsored the bill after reviewing how other states handle the issue. He told the Connecticut Post that he pushed for action after learning Tennessee had recently banned first-cousin marriages and that Connecticut did not have a total ban, which prompted him to look more closely at the issue. Carney said the aim was to align Connecticut with other states and address a gap in the law without retroactively penalizing marriages that occurred when the practice was legal.

State Rep. Steve Stafstrom, a Democrat from Bridgeport who co-sponsored the bill, said the push is grounded in science. He noted that procreation between first cousins has been shown to increase the chances of birth defects, a point corroborated by reviews in medical literature cited by the bill’s supporters. The measure, he said, closes an outlier status in state policy and protects future generations from preventable health risks.

Cousin marriage was legal in all then-34 states before the Civil War. Today, it is prohibited in 26 states, with a variety of approaches in the remainder. Connecticut and New Hampshire are the only New England states that strictly prohibit the union, while Maine permits it in some cases with genetic counseling or other requirements. Beyond New England, states differ markedly: some bar the practice entirely, while others permit it with caveats such as age or infertility, or require genetic assessments before marriage.

In Minnesota, for example, first-cousin marriages are permitted only under established customs of aboriginal cultures, according to current statutes, while North Carolina restricts marriage to double first cousins (the children of two sisters who married two brothers). The regional and national landscape reflects enduring debates over family law, genetics, and public health considerations.

Connecticut will become the 26th state to ban first-cousin marriages outright, a shift that reflects ongoing policy debates about how best to regulate intimate family relationships in the interest of public health and social policy. The measure passed in a year when bipartisan cooperation yielded a rare cross-party agreement on a social issue in a Democratic-dominated legislature, underscoring a continued focus on modernizing state law.

The law will apply prospectively starting Oct. 1, and lawmakers indicated there are no intended retroactive penalties for marriages that occurred before that date. As implementation nears, supporters insist the change will reduce health risks associated with consanguinity and bring Connecticut in line with a growing number of states that have chosen to prohibit the practice entirely.