Marrying a close relative raises eyebrows in many places, but Ohio’s rules are clear on cousins. The state’s marriage laws strictly limit who can tie the knot based on kinship, making first-cousin unions a no-go for official licenses.​
Ohio’s Core Marriage Statute
Ohio Revised Code Section 3101.01 sets the rules for who can legally marry. It states that only individuals “not nearer of kin than second cousins” may be joined in marriage, provided they meet age and other requirements like being unmarried.
This means first cousins—sharing grandparents—are too closely related to qualify. County probate courts, which issue licenses, enforce this by denying applications to anyone closer than second cousins.
Second cousins, who share great-grandparents, and more distant relatives face no such bar. The law aims to prevent incestuous ties while allowing looser family connections.​
What Counts as “Nearer of Kin”?
First cousins are directly prohibited as they fall under “nearer than second cousins.” This also covers first cousins once removed, like a parent’s first cousin.
The phrase originates from older statutes but remains unchanged in recent versions, last updated in 2019 with no kinship alterations by 2026.
No recent amendments in 2025 or 2026 have loosened these restrictions, keeping the second-cousin threshold firm.​
Legal Status: Prohibited, Not Always Void
While the statute bars first-cousin marriages from being performed in Ohio, they aren’t automatically “void ab initio” like same-sex marriages under the same code.
In the 1958 Ohio Supreme Court case Mazzolini v. Mazzolini, justices ruled that first-cousin marriages aren’t void because they’re not expressly declared so, not incestuous per common law, and not “shocking to good morals.”
Dissenters argued the statute implies prohibition via expressio unius est exclusio alterius—mentioning second cousins excludes closer ones—but the majority upheld validity in that context.​
Today, you simply can’t get a license, making it effectively illegal to marry first cousins in-state. Performed anyway (e.g., common-law), it might hold under common law but lacks state recognition for benefits.
Penalties and Practical Consequences
No criminal penalties exist for attempting a first-cousin marriage in Ohio—unlike closer relations like siblings, which are incest felonies.​
The main hit is administrative: denied licenses mean no official ceremony. Out-of-state first-cousin marriages may not be recognized if challenged, complicating inheritance, taxes, or divorce.
Sexual relations between first cousins aren’t illegal or incestuous, as Ohio’s criminal code focuses on closer kin.​
Comparison Across U.S. States
Ohio joins about half the states restricting first-cousin marriage. Here’s a quick table:
Nationwide, 19 states ban first-cousin marriage outright.​
Health and Cultural Context
Beyond law, first-cousin marriages carry genetic risks—offspring have 4-7% higher chance of birth defects versus 3-4% general population—due to shared DNA.​
Culturally, cousin marriage is taboo in the U.S. but common globally (10% of marriages worldwide). Ohio’s law reflects Western norms prioritizing genetic diversity.​
Out-of-State Marriages and Advice
Couples marrying first cousins elsewhere (e.g., West Virginia) might face Ohio non-recognition for residency benefits.​
For personalized cases, consult an Ohio family lawyer or probate court. Laws evolve, so verify via codes.ohio.gov as of March 2026.
​Sources
- https://codes.ohio.gov/ohio-revised-code/section-3101.01/5-7-2004
- https://codes.ohio.gov/ohio-revised-code/section-3101.01
- https://en.wikipedia.org/wiki/Cousin_marriage_law_in_the_United_States
- https://owossoindependent.com/is-it-illegal-to-marry-your-cousin-in-ohio-heres-what-the-law-says/
