Yes, first cousins can marry in the United States, but only in some states. About 18 states plus the District of Columbia allow first-cousin marriage with no special conditions, roughly 7 allow it only when the couple meets age or fertility requirements, and the remaining 25 prohibit it. In a handful of prohibiting states, the relationship itself can trigger criminal charges. Because a marriage license is issued under state law, the answer to whether you can marry your first cousin depends entirely on which state you apply in — and, if you later move, on which state you end up living in.
Where First Cousins Can Marry Without Conditions
In these states, first cousins apply for a marriage license the same way any unrelated couple would. No genetic testing, no age minimums, no extra paperwork:
- Alabama
- Alaska
- California
- Colorado
- Connecticut
- Florida
- Georgia
- Hawaii
- Maryland
- Massachusetts
- New Jersey
- New Mexico
- New York
- North Carolina
- Rhode Island
- South Carolina
- Vermont
- Virginia
- District of Columbia
These jurisdictions place first cousins outside the “prohibited degrees” of relationship that cover parents, children, siblings, aunts, uncles, nieces, and nephews. Application fees and requirements are identical to those for unrelated applicants.
States That Allow First-Cousin Marriage With Conditions
Seven states permit these marriages only when narrow requirements are met. Most conditions aim at the same thing: allowing the marriage while reducing the likelihood of biological children.
Age-Based Requirements
Indiana is the strictest. Both cousins must be at least 65 before a clerk will issue the license.1Indiana General Assembly. Indiana Code 31-11-1-2 – Marriage to Close Relative Prohibited; Marriages Between Cousins; Exceptions
Arizona also requires both parties to be 65 or older. Couples where one or both are younger can petition a superior court judge for approval by proving that one cousin is unable to reproduce.2Arizona Legislature. Arizona Revised Statutes 25-101 – Void and Prohibited Marriages
Utah uses two tiers. Both cousins 65 or older can marry without court involvement. If both are 55 or older but under 65, they need a district court to find that either party is unable to reproduce. Note that both parties must be at least 55 for the court path — not just one.3Utah Legislature. Utah Code 30-1-1 – Incestuous Marriages Void
Illinois permits the marriage when both cousins are 50 or older, or when a licensed physician certifies that at least one of them is permanently and irreversibly sterile. The medical certification must be filed with the license application. Wisconsin sets the woman’s age threshold at 55, or allows the marriage if either party is permanently sterile.
Genetic Counseling
Maine takes a different route. First cousins must obtain a physician’s certificate of genetic counseling before the clerk will issue a license.4Maine State Legislature. Maine Code Title 19-A 701 – Prohibited Marriages; Exceptions The couple isn’t prohibited from having children; they simply have to consult a medical professional about hereditary risks first. No certificate, no license.
Minnesota’s Narrow Exception
Minnesota generally prohibits first-cousin marriage but carves out an exception for marriages “permitted by the established customs of aboriginal cultures.” That effectively limits legal cousin marriage in the state to members of Native American communities following traditional practices. For everyone else, the ban applies.
States That Prohibit First-Cousin Marriage
Twenty-five states flatly ban marriages between first cousins. In most of them, the marriage is void from its inception, meaning it never had legal effect. A clerk will deny the license once the relationship is disclosed. States in this group include Arkansas, Delaware, Idaho, Kansas, Kentucky, Louisiana, Michigan, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Dakota, Texas, Washington, West Virginia, and Wyoming. These statutes commonly group cousin marriages together with unions between closer relatives under labels like “prohibited degrees of consanguinity.”5U.S. Department of State Foreign Affairs Manual. 9 FAM 102.8 – Family-Based Relationships
The distinction between “void” and “voidable” matters. A void marriage is treated as if it never existed. Neither party needs a court order to dissolve it because there’s nothing to dissolve. A voidable marriage is technically valid until a court declares it invalid. Most ban states classify cousin unions as void, which carries serious consequences for property rights, inheritance, and benefit claims.
Criminal Penalties in Some Prohibiting States
Most ban states simply treat the marriage as void. About eight go further and can bring criminal charges against first cousins who marry or engage in sexual relations: Arizona, Nevada, North Dakota, Oklahoma, South Dakota, Texas, Utah, and Wisconsin.
Penalties vary widely. Some states classify the offense as a misdemeanor; others treat it as a felony carrying years in prison. Alabama’s incest statute, which covers first cousins in some circumstances, carries a potential sentence of one to ten years. Arkansas law allows three to ten years for a first offense. Alaska and Arizona impose sentences ranging from one to five years. Fines can reach $5,000 to $15,000 or more depending on the state and offense level. A felony conviction can also affect employment background checks and professional licensing, and some states impose registration requirements.
Actual prosecution of consenting adult cousins is rare, and many of these statutes were drafted with closer family relationships in mind. The exposure is nonetheless real, and a couple that moves into one of these states after marrying elsewhere could in theory face charges over a marriage that was legal where performed.
Will Your Marriage Be Recognized If You Move?
The default rule in American law is that a marriage valid where celebrated is valid everywhere. You don’t normally lose your married status by driving across a state line. Cousin marriages are one of the areas where this rule breaks down.
Many states that ban first-cousin marriage refuse to recognize one performed elsewhere when it conflicts with what courts call the state’s “strong public policy.” Some go further with marriage evasion statutes that specifically target couples who leave the state to sidestep local restrictions and then return. If a court finds the couple traveled solely to circumvent the home state’s ban, it can declare the marriage void once they’re back. Spousal inheritance rights, health insurance coverage, hospital visitation authority, and standing in family court can all disappear.
Courts differ in how aggressively they enforce these limits. The outcome often depends on the wording of the ban. States that declare cousin marriages “void” tend to apply their prohibition more rigidly than states that merely say such marriages “shall not be contracted” within the state’s borders. If you’re considering marrying and then moving, research the law of the state where you plan to live, not just the state where you plan to marry.
Federal Benefits Don’t All Follow the Same Rule
Federal agencies don’t agree on how to treat cousin marriages, and the split can determine whether you collect spousal benefits or get treated as a legal stranger. Some agencies look at where the marriage was performed. Others look at where the couple lives.
Taxes and FMLA Leave
The IRS follows a place-of-celebration rule. Under Revenue Ruling 2013-17, a marriage is recognized for federal tax purposes as long as it was legally entered into where performed, even if the couple later moves to a state that wouldn’t have allowed it.6Internal Revenue Service. Revenue Ruling 2013-17 Cousins who married in California and moved to Texas can still file joint federal returns.
The Department of Labor uses the same approach for the Family and Medical Leave Act. FMLA defines “spouse” based on the law of the state where the marriage was entered into, so a cousin marriage from a permissive state should qualify the couple for spousal FMLA leave even if their current state bans such unions.7U.S. Department of Labor. Fact Sheet #28L – Leave Under the Family and Medical Leave Act When You and Your Spouse Work for the Same Employer
Social Security
The Social Security Administration uses the opposite rule, and the stakes are high. Under Section 216(h)(1)(A) of the Social Security Act, the SSA determines marital status based on the laws of the state where the worker was domiciled when benefits are claimed, or at the time of death for survivor benefits. If that state considers first-cousin marriages void, the SSA will not recognize the marriage, even one legally performed elsewhere.8Social Security Administration. SSR 63-20 – Section 216(h) – Validity of Marriage Between First Cousins
The SSA has also ruled that the “deemed valid” marriage provision — which sometimes preserves marriages with procedural defects — does not apply to cousin marriages. The agency treats the close familial relationship as a substantive legal impediment rather than a procedural one, so there’s no fallback.8Social Security Administration. SSR 63-20 – Section 216(h) – Validity of Marriage Between First Cousins A surviving spouse in this situation can lose tens of thousands of dollars in survivor benefits. Couples who marry in a permissive state but retire to a prohibiting one are the ones most often blindsided.
Immigration
For immigration purposes, USCIS evaluates a cousin marriage based on the laws and public policy of the state where the couple resides or intends to reside. If USCIS approves a family-based petition knowing that the parties are first cousins, the State Department generally accepts that determination.5U.S. Department of State Foreign Affairs Manual. 9 FAM 102.8 – Family-Based Relationships If the intended state of residence considers the marriage void or criminalizes the relationship, that public policy conflict can result in denial. Claiming residence in a permissive state solely to sidestep the issue won’t work, because USCIS looks at where the couple actually intends to live.
Why Some States Restrict These Marriages
The rationale behind most conditional and prohibitory laws is medical. First cousins share roughly 12.5% of their genetic material, which raises the odds that both carry the same recessive gene for a disorder. A child born to first cousins carries roughly a 6% chance of a recessive genetic disorder, compared to about 3% for the general population. A large peer-reviewed study found an adjusted odds ratio of 1.59, reflecting about a 60% increase in birth defect risk after controlling for other factors.9National Center for Biotechnology Information. Consanguinity and Birth Defects in the Jerusalem Perinatal Study The increase is real but modest in absolute terms, which is why some states focus on reproductive capacity through age or sterility conditions rather than outright bans, and why Maine settles for genetic counseling.
Children Born to Voided Cousin Marriages
Parents in void marriages often worry about their children’s legal status. Most states have statutes protecting children born to void marriages, generally providing that the child is considered legitimate regardless of whether the parents’ marriage was legal. That preserves the child’s rights to inheritance, child support, and the legal parent-child relationship with both parents.10Social Security Administration. SSA Handbook 326 – Are Children of Void Marriages Legitimate
The specifics vary. Some states confer legitimacy automatically by statute. Others may require a court to declare the child legitimate formally. Either way, the child’s protections are generally far stronger than the parents’ marital rights in a prohibiting state. A child born to first cousins whose marriage is voided in Ohio, for example, does not lose their claim to inheritance from either parent, even though the parents themselves have no spousal rights.
Second Cousins and More Distant Relatives
Second cousins are often confused with first cousins, but the legal picture is very different. Second cousins — people who share great-grandparents but not grandparents — can legally marry in every state except Kentucky and Nevada, the only two that extend their prohibitions that far. Everywhere else, second-cousin marriage is treated the same as marriage between unrelated individuals. Third cousins and more distant relatives face no restrictions anywhere in the country.