Is It Illegal to Marry Your Cousin in Idaho? Here’s What the Law Says

The topic of cousin marriage can spark a range of reactions – some find it unusual or taboo, while in certain cultures, it’s a common practice. Popular culture often depicts Idaho as a place where anything goes, so some wonder if that extends to marrying close relatives. Let’s dive into Idaho’s specific laws concerning cousin marriages.

Idaho State Law on Cousin Marriage

Idaho state law has a clear stance on the legality of cousin marriages:

  • Idaho Code Section 32-206: “All marriages between first cousins are prohibited.”

This means that individuals who are the children of siblings cannot legally marry each other in the state of Idaho.

  • Exceptions: There are limited exceptions to this rule:
    • Age: Marriage may be allowed between first cousins if the female partner has reached the age of 55.
    • Sterility: Marriage can be contracted if either partner can provide a signed affidavit from a physician confirming permanent sterility.

Why are Cousin Marriages Restricted?

There are two primary reasons behind restrictions on cousin marriages:

  • Potential Genetic Risks: Close relatives share a higher percentage of genetic material. If both partners carry a recessive gene for a particular disorder, the chances of their offspring inheriting two copies (and thus developing the disorder) increase significantly.
  • Social and Cultural Norms: In many Western societies, including the United States, marrying a close relative is often viewed as socially unacceptable or taboo. These cultural norms influence both public opinion and legal restrictions.

Prevalence of Cousin Marriage in the United States

Cousin marriage laws vary significantly from state to state within the US. Here’s a general picture:

  • States Allowing First-Cousin Marriage: Roughly half of the states in the US permit marriages between first cousins with varying levels of restrictions or with no limitations at all.
  • States with Restrictions or Bans: The other half of US states have laws either explicitly prohibiting first-cousin marriage or imposing additional conditions on such unions (such as age or sterility requirements).

Idaho’s Position Relative to Other States

Idaho falls into the category of states that prohibit marriage between first cousins, with the limited exceptions noted earlier. This puts it in line with a significant portion of US states. It’s helpful to view Idaho’s law in the broader context of US marriage laws.

Ethical and Moral Considerations

The topic of cousin marriage often raises ethical and moral questions. Here are some key points within the debate:

  • Diverse Perspectives: There is no single, universally accepted moral stance on cousin marriage. Perspectives are influenced by cultural backgrounds, religious beliefs, and personal convictions.
  • Individual Choice vs. Societal Implications: Some argue that consenting adults should have the right to marry whomever they choose, while others emphasize the potential negative consequences for offspring and the wider social fabric.

Where to Find Further Information

If you seek more details on Idaho’s marriage laws or cousin marriage in general, here are reliable sources:

  • Idaho State Legislature Website: ( – Offers the official text of state laws.
  • National Conference of State Legislatures (NCSL): ( – Provides information on marriage laws across different US states.
  • Cornell Law School: Legal Information Institute: ( – Offers resources and analysis on various legal topics, including marriage.

Historical Context of Cousin Marriage Laws

It’s worth noting that laws restricting cousin marriage are a relatively recent development in Western history. Throughout much of human history, cousin marriage was a common practice for various reasons, including:

  • Strengthening Family Ties: Marrying within the family helped consolidate wealth, property, and political alliances.
  • Limited Social Mobility: In smaller communities with limited options, marrying a cousin might have been seen as a practical necessity.

The shift away from cousin marriage in the Western world began largely in the 19th century, influenced by emerging scientific understanding of genetics and a growing emphasis on individual choice in marriage.

Practical Considerations

For those considering marriage where laws may present obstacles, here are important factors to weigh:

  • Medical Consultation: Couples who are closely related should strongly consider seeking genetic counseling before deciding to have children. This can assess potential risks and provide information for making informed family planning decisions.
  • Relocation Options: If a couple is determined to marry but faces legal restrictions in their state, they may consider relocating to a jurisdiction where their union would be legally recognized.
  • Alternatives to Traditional Marriage: Couples might choose to form a committed partnership without seeking legal marriage, potentially enjoying many of the same social and emotional benefits.


Idaho’s laws on cousin marriage reflect a balance between acknowledging the potential genetic risks of such unions while allowing for limited exceptions under specific circumstances. While the state’s stance aligns with many other US states, the ethics and implications of cousin marriage remain a matter of ongoing debate.

Ultimately, the decision of whether or not to marry a close relative is a deeply personal one. Couples facing this situation should consider the legal restrictions in their location, seek appropriate medical guidance, and weigh their own values and beliefs when making such important life choices.

Important Disclaimer This article provides legal information but does not constitute legal advice. It’s always advisable to consult a qualified legal professional for advice tailored to your specific circumstances.

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MBS Staff
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