Marrying a first cousin is illegal in Missouri under state law, which explicitly prohibits such unions. However, the state allows some related activities and distinguishes between different degrees of cousin relationships.
Legal Prohibition in Missouri
Missouri Revised Statutes §451.020 declares marriages between first cousins “presumptively void,” meaning they are not legally recognized. This prohibition applies regardless of whether the cousins are related by blood or adoption. Attempting to obtain a marriage license for a first-cousin union is unlawful, and officials issuing such licenses knowingly can face misdemeanor charges.
Permitted Activities
While marriage is banned, Missouri law permits:
- Cohabitation: First cousins can legally live together.
- Sexual relations: No criminal penalties exist for consensual relationships between adult first cousins.
Cousin-Marriage Exceptions
Missouri allows marriages involving more distant relatives:
- First cousins once-removed (e.g., a cousin’s child) can legally marry.
- Half-cousins (sharing one grandparent) face no restrictions.
Comparative Context
Missouri is among 24 U.S. states prohibiting first-cousin marriages, contrasting with neighboring states like Kentucky (illegal) and Illinois (allowed only if partners meet age/fertility criteria). While some states permit such unions under specific conditions (e.g., genetic counseling in Maine), Missouri maintains a blanket ban.
Legal Risks
Attempting to marry a first cousin in Missouri renders the union legally invalid. Residents cannot circumvent the law by marrying in another state—Missouri voids such marriages if either spouse resides in the state.
In summary, Missouri strictly prohibits first-cousin marriages but imposes no restrictions on cohabitation, sexual relationships, or marriages with more distant cousins like first cousins once-removed.
Sources
- https://en.wikipedia.org/wiki/Cousin_marriage_law_in_the_United_States
- https://www.draslamabdullah.com/post/first-cousin-marriage-laws-in-the-u-s
- https://www.mec.mo.gov/WebDocs/PDF/Misc/RelationshipChart.pdf
- https://www.insideedition.com/gallery/kissing-cousins-states-where-marrying-your-relative-legal-48234
- https://revisor.mo.gov/main/OneSection.aspx?section=451.020